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Biomedical subjects

C J Davis

Publications and source records attributed to C J Davis.

At least 109 records · Page 6Linked to original sources
PubMed1978

The peroneal muscular atrophy syndrome: clinical, genetic, electrophysiological and nerve biopsy studies. I. Clinical, genetic and electrophysiological findings and classification.

1. A clinical, genetic, electrophysiological and nerve biopsy study of 49 index cases with peroneal muscular atrophy is reported. 2. In dominantly inherited cases, motor conduction velocities of the upper limbs within kinships indicated segregation into five groups which we have termed: a) hypertrophic neuropathy (less than 25 m/sec); b) intermediate group (25-45 m/sec); c) neuronal sensorimotor neuropathy (greater than 45 m/sec); d) neuronal motor neuropathy (greater than 45 m/sec); e) neuronal motor neuropathy with upper motor neurone involvement (greater than 45 m/sec). 3. The intermediate group is distinguished from the hypertrophic neuropathy group by the absence of clinically observed nerve hypertrophy and by the presence of a number of clinical features, including a more rapidly progressive disease. It is concluded to be genetically separate. This group is similarly quite distinct from the neuronal groups. Nerve biopsy studies support this view (Madrid et al., 1977; Bradley et al., 1977). 4. There was a relationship between severity of the disease and the conduction velocity which was most evident in the intermediate group. 5. There appeared to be an increase in motor conduction velocity with age in the hypertrophic neuropathy group, while the velocity fell in older patients in the intermediate group. 6. Sensory conduction velocity generally paralleled motor velocity but showed relatively less reduction. 7. Upper motor neurone features were not uncommon, appearing particularly in the intermediate group. Their presence may not therefore be a reliable basis for the classification of cases of peroneal muscular atrophy. 8. Tremor was observed in the hypertrophic, intermediate and neuronal motor neuropathy groups of patients, and does not provide a useful criterion for the classification of peroneal muscular atrophy. 9. There was occasional evidence to suggest poor or abnormal expression of the gene in dominantly inherited cases. Until more specific markers are available sporadic cases should be classified on the basis of the dominant forms, though they show a greater variability.

England↗
PubMed1977

The peroneal muscular atrophy syndrome. Clinical, genetic, electrophysiological and nerve biopsy studies. Part 2. Observations on pathological changes in sural nerve biopsies.

The light-and electron-microscopic, single teased nerve and morphometric studies of a series of 17 sural nerve biopsies from patients with personeal muscular atrophy are presented. The cases are divided into the following groups according to the criteria of Davis, Bradley and Madrid (1977): Hypertrophic Neuropathy Group; Intermediate Group; Neuronal Sensorimotor Group; Neuronal Motor Group. The Hypertrophic Neuropathy Group had nerve hypertrophy and marked segmental demyelination and onion bulb formation. The Intermediate Group also had segmental demyelilination and onion bulb formation, but nerve hypertrophy was not seen, and axonal degeneration and regeneration were prominent. The Neuronal Sensorimotor Group cases were all sporadic, and showed some onion bulbs, paranodal demyelination and evidence of axonal degeneration and regeneration. The sensory nerve biopsy in the Neuronal Motor Group showed no major abnormality apart from some cluster formation indicating axonal regeneration. The data tend to support the classification of peroneal muscular atrophy proposed by Davis et al. (1977), though there was overlap between the groups in individual pathological parameters.

Adolescent↗
PubMed1977

The peroneal muscular atrophy syndrome. Clinical genetic, electrophysiological and nerve biopsy studies. Part 3. Clinical, electrophysiological and pathological correlations.

This report analyses correlations between clinical, electrophysiological and pathological data derived from a series of families with peroneal muscular atrophy. It was found that the observed differences between families in median nerve forearm motor conduction velocity were unlikely to be due to differences in the age or severity of the cases. Similarly it it was unlikely that the pathological differences between cases were due to age or severity of the case. The conduction velocity in the Hypertrophic Neuropathy Group tended to increase slightly with age, while that in other cases tended to fall slightly. The conduction velocity and total myelinated fibre counts were inversely related to the degree of segmental demyelination. The Hypertrophic Neuropathy Group and the Intermediate Group of cases were found to behave differently in a number of correlative analyses, thus supporting the suggestion that they represent different disease entities.

Adolescent↗
PubMed1977

The effect of prolonged inactivity upon the contraction characteristics of fast and slow mammalian twitch muscle.

1. Prolonged inactivity of soleus (slow twitch) and medial head of flexor digitorum longus (fast twitch: previously commonly known as flexor hallucis longus and hereafter referred to as FDL) muscles of the cat was produced by sodium pentobarbitone anaesthesia or spinal isolation. Isometric contraction characteristics were examined after 4-22 days and 8-49 days respectively.2. Sleep of up to 3 weeks' duration was associated with progressive changes in the weight, maximum tetanic tension, speed of contraction and absolute refractory period of fast twitch muscle. The slow muscle showed corresponding changes which were not so pronounced. Cord isolation resulted in similar changes which tended to be reversed after longer periods of disuse.3. Fast muscle frequently exhibited an after-contraction with corresponding electromyographic activity following two weeks or more of disuse.4. The time to peak of FDL was prolonged, becoming approximately one and a half times normal. In contrast to other reports of disuse, that of soleus was normal or slightly prolonged.5. The ratio of twitch to tetanic tension of FDL increased to twice the normal value or greater and remained high. The soleus muscle showed a smaller increase with evidence of a return towards normal after longer periods of inactivity.6. Absolute refractory period of FDL was considerably prolonged (more than 50%) following barbiturate sleep and this also occurred, but to a lesser degree, with soleus after 4-7 weeks of cord isolation.7. The observation that inactivity produced slowing rather than an increased speed of switch contraction indicates that aggregate activity is not the controlling factor. Changes seen in the contraction characteristics of FDL are noted to show a general similarity to those occurring following denervation.

Anesthesia, General↗
PubMed1976

Evidence for an adenosine receptor on the surface of dog coronary myocytes.

Adenosine and theophylline were linked covalently to oxidized stachyose to produce compounds too large to penetrate cell membranes. These compounds were used in two conscious and six open-chest anesthetized dogs to test the hypothesis that there is an adenosine receptor on the surface of the coronary myocyte. Intracoronary infusions of the adenosine derivative produced dose-dependent coronary vasodilation which was antagonized by theophylline; two types of theophylline derivative antagonized the coronary vasodilatory action of adenosine. Although these results show that both adenosine and theophylline exert their coronary effects at the surface of the smooth muscle cells, this evidence does not establish that they are competing for a common receptor.

Adenosine↗
PubMed1975

Comparison of House-Tree-Person drawings of young deaf and hearing children.

The House-Tree-Person (H-T-P) drawings of a matched sample of 80 deaf and 80 hearing school children, ages 7 through 10 years, were compared to assess differences related to the handicap, and the capacity of the H-T-P to distinguish between children rated by their teachers as poorly adjusted and those rated well adjusted. No differences were found between deaf and hearing in the drawing of the ear or mouth of the human figure. There was a very significant difference in the drawing of the branch structure of the tree. There were no differences in numbers of indicators of disturbance in the drawings of the children rated as more or as less well adjusted.

Achievement↗
PubMedDate not supplied

Papillary renal cell carcinoma: ultrasonic/pathologic correlation.

Papillary renal cell carcinoma represents a separate clinicopathologic entity distinguished from nonpapillary renal cell carcinoma by angiography, microscopic pathology, and biological behavior. We correlated retrospectively 11 surgically proven papillary renal cell carcinomas with ultrasound patterns and gross pathologic findings. In addition, we reviewed retrospectively 65 surgically proven cases of nonpapillary renal cell carcinoma for sonographic patterns. Seven of 11 (64%) of the papillary tumors were less echogenic than the ipsilateral renal cortex (hypoechoic). Only 23% of the nonpapillary tumors were hypoechoic. These data suggest that renal papillary carcinoma tends to be hypoechoic on ultrasound. In most of the papillary cases, this hypoechoic pattern was due to a large central area of cystic necrosis within the tumor.

Adenocarcinoma↗
PubMedDate not supplied

Laparoscopic cholecystectomy combined with endoscopic sphincterotomy and stone extraction or laparoscopic choledochoscopy and electrohydraulic lithotripsy for management of cholelithiasis with choledocholithiasis.

Six hundred twenty-two laparoscopic cholecystectomies were performed at St. Vincent Hospital over a 14-month period. We reviewed the records of 366 of these patients who were referred to the authors. Thirty-six patients had suspected choledocholithiasis. The primary author (M.E.A.) performed 38 endoscopic retrograde cholangiopancreatography (ERCPs) on these patients for diagnosis and management. Seventeen of the 36 patients had common bile duct stones; 19 patients had negative studies. Of the 17 patients with choledocholithiasis, 15 had successful cannulation of the common bile duct, and, of these, 10 underwent laparoscopic cholecystectomy plus endoscopic sphincterotomy and extraction of the common duct stone(s). In one high-risk elderly patient, we extracted the stone from the common duct and left the gallbladder in situ. Two patients failed endoscopic cannulation and underwent open cholecystectomy with common bile duct exploration. Four additional patients, cannulated successfully, had unsuccessful endoscopic stone removal because the stones were too large or were impacted. Two of these patients underwent open cholecystectomy and common duct exploration. The two other patients underwent laparoscopic cholecystectomy and choledochoscopy through the cystic duct with the flexible choledochoscope. An electrohydraulic lithotripsy probe was then inserted through the choledochoscope to fragment the stones, and stone fragments were allowed to pass through the previously created sphincterotomy. We believe our data, supported by data in the literature, show that these alternative methods for treating choledocholithiasis are safe and effective and should be considered primary modalities for treating this condition now that laparoscopic cholecystectomy is the treatment of choice for cholelithiasis.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMedDate not supplied

Adult renal hamartomas.

Renal angiomyolipomas, the most familiar of the renal hamartomas, are well known to radiologists, despite being uncommon and of limited clinical importance, because angiomyolipomas represent one of the few lesions for which a specific diagnosis can be achieved on the basis of radiologic findings in the majority of cases. Because of the diversity in the relative amounts of various cellular components and because of the occasional association with acute hemorrhage, the radiologic features of angiomyolipomas can be somewhat varied. At sonography, angiomyolipomas appear echogenic with acoustic shadowing. At computed tomography (CT), these lesions typically appear as well-marginated, small (< 5 cm in size), cortical masses of predominantly fat attenuation with heterogeneous soft-tissue attenuation interspersed throughout. Some angiomyolipomas are larger and poorly marginated because of hemorrhage. Typical angiomyolipomas are largely composed of fat; those uncommon tumors without demonstrable fat cannot be radiologically distinguished from renal cell carcinoma. Renal leiomyoma, a lesion that pathologically overlaps with angiomyolipoma to some degree, has a quite different imaging appearance (ie, homogeneous, without detectable fat) that cannot be distinguished from malignant renal lesions.

Adult↗
PubMedDate not supplied

Transitional cell carcinoma of the urinary tract: radiologic-pathologic correlation.

The urothelium is a target tissue for carcinogens that lead to the development of transitional cell carcinomas (TCCs), both synchronous and metachronous. Although there are pathologic and imaging features common to transitional cell tumors occurring anywhere in the genitourinary tract, certain findings are more typical of tumors of the renal pelvis, ureter, or urinary bladder. A slightly irregular, fixed mass arising from any urothelial surface is characteristic of TCC. Although such masses are usually confined to the collecting system lumina, larger lesions that arise in the renal pelvis may extend into the renal parenchyma, typically in an infiltrative pattern that preserves the reniform shape. In contrast to the rapidly developing mural edema associated with obstructing calculi, the relatively slow growth of ureteral TCC allows for gradual expansion of the ureteral lumen around the tumor and is less likely to produce acute renal colic. Focal wall thickening, either eccentric or circumferential, may also be a manifestation of TCC of the ureter or, less commonly, other portions of the urinary tract. The urinary bladder is the most common site of TCC; lesions are generally confined to the lumen and typically do not extend beyond the bladder wall until quite large.

Adult↗