A single-pulse transcranial magnetic stimulus (TMS) may induce contraction in many muscles of the body at the same time. This is specially the case when using the double-cone coil to obtain the motor evoked potentials in leg muscles. Even if intensity is kept below threshold for the soleus muscle, TMS induces facilitation of the soleus H reflex that is separated into two phases: the first, peaking at 10-20 ms and the second, peaking at 70-90 ms. We investigated the possibility that TMS-induced facilitation of the H reflex was related, at least in part, to the reafferentation volley reaching the alpha motoneuron after synchronized contraction of other muscles in the body. To test this hypothesis, we examined the effects of vibration on the TMS-induced facilitation of the soleus H reflex. As expected, vibration applied over the triceps tendon caused a significant reduction in H reflex amplitude: 42.4 ± 6.4 % of control values. When conditioned by TMS at intervals corresponding to the first phase, the H reflex was facilitated to the same extent in both conditions: with and without vibration. However, at intervals corresponding to the second facilitation phase, there was a significantly reduced facilitation with vibration. These differential effects of vibration on the two phases of the TMS-induced facilitation of the H reflex indicate a different mechanism for each facilitation phase. The first phase could result from direct corticospinal excitatory input, while the second phase might depend on inputs via Ia afferents from heteronymous muscles.
The assessment of functional deficits in small fibre neuropathies (SFN) requires using ancillary tests other than conventional neurophysiological techniques. One of the tests with most widespread use is thermal threshold determination, as part of quantitative sensory testing. Thermal thresholds typically reflect one point in the whole subjective experience elicited by a thermal stimulus. We reasoned that more information could be obtained by analyzing the subjective description of the ongoing sensation elicited by slow temperature changes (dynamic thermal testing, DTT). Twenty SFN patients and 20 healthy subjects were requested to describe, by using an electronic visual analog scale system, the sensation perceived when the temperature of a thermode was made to slowly change according to a predetermined pattern. The thermode was attached to the left ventral forearm or the distal third of the left leg and the stimulus was either a monophasic heat or cold stimuli that reached 120% of pain threshold and reversed to get back to baseline at a rate of 0.5 °C/s. Abnormalities seen in patients in comparison to healthy subjects were: (1) delayed perception of temperature changes, both at onset and at reversal, (2) longer duration of pain perception at peak temperature, and (3) absence of an overshoot sensation after reversal, ie, a transient perception of the opposite sensation before the temperature reached again baseline. The use of DTT increases the yield of thermal testing for clinical and physiological studies. It adds information that can be discriminant between healthy subjects and SFN patients and shows physiological details about the process of activation and inactivation of temperature receptors that may be abnormal in SFN.
Hamartomatous polyps of Peutz-Jeghers type are strongly associated with Peutz-Jeghers polyposis syndrome and are predominantly encountered in the small intestine. Sporadic cases are uncommonly reported. We report a case of a polyp identified incidentally in the appendix of a patient undergoing diagnostic imaging due to a history of hepatitis C infection. Histopathologic evaluation after appendectomy showed a polyp with bands of muscularis mucosae bundles with arborizing architecture and variable amounts of inspissated mucin, morphologically indistinguishable from Peutz-Jeghers type hamartomatous polyp. A family or personal history of abdominal cancers was not reported by the patient, suggesting a sporadic occurrence. Next generation sequencing revealed only two pathogenic low-level STK11 mutations, presumed to be somatic. In conclusion, this is an unusual case of a sporadic Peutz-Jeghers type polyp occurring in the appendix.
Background Plasmacytoid urothelial carcinoma (PUC) is a rare but aggressive variant of transitional cell carcinoma. In patients with unresectable disease, cisplatin-based combination chemotherapy is the most commonly used treatment. However, many patients are cisplatin-ineligible due to poor performance status or other comorbidities. We report a case of a cisplatin-ineligible patient with metastatic PUC who was treated with pembrolizumab. Case report A 71-year-old man with 30 pack-year smoking history and schizoaffective disorder was found to have multiple right-sided lung nodules after presenting with atypical chest pain. Staging CT showed bilateral adrenal masses and a large soft tissue mass in the right iliac fossa. Tissue pathology and immunohistochemical staining was consistent with PUC. As the patient was cisplatin-ineligible due to poor performance status and multiple medical comorbidities, the decision was made to treat with pembrolizumab. Repeat CT chest and abdomen showed partial response at three months and stable disease at six months. Discussion The KEYNOTE-052 study found that first-line pembrolizumab in cisplatin-ineligible patients with urothelial cancer resulted in complete or partial response in 24% of patients with few adverse effects. However, it is unclear if patients with plasmacytoid variant were included. To our knowledge, this is the first case report of a patient with metastatic PUC not only treated with pembrolizumab but shown to have clinical response. Conclusion Given our patient’s clinical response, pembrolizumab is a promising first-line agent for treating cisplatin-ineligible patients with metastatic PUC. Further evaluation is warranted to confirm the benefit of treating this patient population with pembrolizumab.
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