Search PubMed⌕ Search

Biomedical subjects

D Rubinstein

Publications and source records attributed to D Rubinstein.

At least 37 records · Page 2Linked to original sources
PubMed1994

Partial development of the corpus callosum.

PURPOSE: To determine whether the MR findings of callosal dysgenesis suggest that the partially formed corpus callosum in humans is the result of arrested growth or delayed continued development. METHODS: The MR scans of 25 patients with callosal dysgenesis were reviewed to determine whether the observed corpus callosum corresponded to the form and position of a portion of a normal corpus callosum, as suggested by a theory of arrested growth. RESULTS: In 10 of the 25 cases, the partially formed corpus callosum corresponded to a portion of a normal corpus callosum. In the remaining 15 cases, the partially formed corpus callosum was located posterior to the expected location of a normal genu and inferior to the expected location of a normal body. CONCLUSIONS: Corpus callosum dysgenesis in humans may be caused by arrested growth in some cases; in other cases it is most likely caused by delayed continued development that attempts to compensate for earlier abnormalities in the evolution of midline structures.

Abnormalities, Multiple↗
PubMed1994

Contrast-enhanced fat-suppression neuroimaging.

The commercially available fat-suppression methods currently do not produce quantitative fat suppression but in regions of minimal magnetic susceptibility effects and high magnetic and radiofrequency homogeneity are clinical tools that can increase confidence and specificity of diagnoses when applied appropriately. The advantages of these methods include a reduction in CSMA, improved tissue contrast allowing contrast-enhanced studies in fat-rich regions for greater sensitivity to pathology, and improved staging of lesions. These methods allow better use of the full dynamic range of the gray scale. Future improvements will include thin-section three-dimensional methods and susceptibility correction schemes, which will broaden the indications and increase the usefulness of fat suppression in clinical MR imaging.

Adipose Tissue↗
PubMed1994

Gas in the cavernous sinus.

PURPOSE: To evaluate the significance of cavernous sinus gas identified on head CT scans. METHODS: Head CT scans were viewed prospectively for a period of 3 years. The charts of patients who demonstrated cavernous sinus gas were reviewed. RESULTS: Seventeen patients without head trauma and 10 patients with head trauma demonstrated gas in the cavernous sinus. None of the patients had symptoms or developed symptoms originating in the cavernous sinus. All of the patients without trauma had an intravenous line in place. Sphenoid fractures or basilar skull fractures were not a constant finding in trauma patients with cavernous sinus gas. CONCLUSIONS: In patients without symptoms referable to the cavernous sinus, gas in the cavernous sinus does not appear to be a significant finding. The gas is most likely the result of venous air emboli from intravenous lines or penetrating trauma.

Adult↗
PubMed1992

Intracranial aneurysms in autosomal dominant polycystic kidney disease.

BACKGROUND AND METHODS: Intracranial aneurysms are a feature of autosomal dominant polycystic kidney disease, but their prevalence is uncertain. We studied 92 subjects with autosomal dominant polycystic kidney disease who had no symptoms or signs of any neurologic disorder. To determine the prevalence of intracranial aneurysms, we performed high-resolution computed tomography (CT) in 60 subjects, four-vessel cerebral angiography in 21, and both procedures in 11. RESULTS: Four of the 88 subjects in whom the radiologic studies were successfully completed had intracranial aneurysms (4 percent; 95 percent confidence interval, 0.1 to 9 percent), as compared with the prevalence of 1 percent reported for an angiographic study of the general population. Three of the four subjects had multiple aneurysms. Seven subjects for whom the results of CT studies were suspicious underwent cerebral angiography: two had aneurysms, and five had normal vascular structures that accounted for the suspicious results of tomography. Four subjects who had normal CT imaging studies also had normal angiographic examinations. Eight of the 32 subjects who underwent angiography (25 percent) had transient complications, as compared with 22 of 220 control subjects (10 percent) who did not have polycystic kidney disease (P less than 0.05). We could not identify any risk factor in these subjects that was related to the occurrence of aneurysm. CONCLUSIONS: Asymptomatic intracranial aneurysms appear to be more frequent in people with polycystic kidney disease than in the general population, although our 95 percent confidence interval includes the possibility of no difference. Because cerebral angiography is associated with increased morbidity in people with polycystic kidney disease, we recommend high-resolution CT as a screening test.

Adolescent↗
PubMed1991

Concussion in sports. Guidelines for the prevention of catastrophic outcome.

Concussion (defined as a traumatically induced alteration in mental status, not necessarily with loss of consciousness) is a common form of sports-related injury too often dismissed as trivial by physicians, athletic trainers, coaches, sports reporters, and athletes themselves. While head injuries can occur in virtually any form of athletic activity, they occur most frequently in contact sports, such as football, boxing, and martial arts competition, or from high-velocity collisions or falls in basketball, soccer, and ice hockey. The pathophysiology of concussion is less well understood than that of severe head injury, and it has received less attention as a result. We describe a high school football player who died of diffuse brain swelling after repeated concussions without loss of consciousness. Guidelines have been developed to reduce the risk of such serious catastrophic outcomes after concussion in sports.

Adolescent↗
PubMed1990

Molecular analysis of a germ line-encoded idiotypic marker of pathogenic human lupus autoantibodies.

Id-16/6 is an idiotypic marker found in both IgM and IgG antibodies, as well as in the tissue lesions of patients with SLE. The prototypic Id-16/6+ mAb is 18/2, whose VH3-derived H chain is encoded by an unmutated germ-line gene. We found that the H chains of VH3-derived Id-16/6+ antibodies contain the major determinants of Id-16/6. Moreover, B cell clones from which those antibodies were harvested produce RNA that hybridized under conditions of high stringency to oligonucleotide probes corresponding to the CDR of the VH segment of 18/2. Western blots of Id-16/6+ mAbs with anti-Id confirmed the association of the Id with H chains. Id-16/6 can identify a subgroup of VH3-derived antibodies we have termed the 18/2 CDR family. However, Id-16/6 can also be expressed in some antibodies unrelated to the 18/2 CDR family. No characteristic Ag-binding specificity was found among the members of the 18/2 CDR family. The principal phenotypic feature shared by all known members of the family is Id-16/6.

Amino Acid Sequence↗
PubMed1990

Ectopic pituitary adenoma of the third ventricle. Case report.

Ectopic pituitary adenomas without associated intrasellar adenomas are rare and are usually located in the sphenoid sinus. Most have been reported without modern radiological, endocrinological, or electron microscopic (EM) documentation. The case of a 47-year-old man with a third ventricular, ectopic, clinically nonsecretory pituitary adenoma, which was shown to be a gonadotrophic adenoma by immunohistochemical and EM study, is reported. Neurological examination, extensive neurodiagnostic imaging, surgical anatomical observation, and endocrinological evaluation showed no evidence of neoplasia outside the third ventricle.

Adenoma↗
PubMed1987

Antigen presentation by liver sinusoidal lining cells after antigen exposure in vivo.

The ability of liver sinusoidal lining cells (LSLC), a mixture of Kupffer cells and endothelial cells, to function as antigen-presenting cells (APC) was examined. Guinea pig LSLC were found to present antigen in vitro, albeit somewhat less effectively than a reference population of peritoneal exudate macrophages. The difference in APC function could not be explained by a deficiency of interleukin 1 (IL 1), as LSLC secreted IL 1 and expressed membrane-bound thymocyte stimulatory activity. The ability of LSLC to take up antigen from the portal blood in vivo and present it to primed T lymphocytes in vitro was also investigated. Trinitrophenyl-ovalbumin was injected intraportally into either strain 13 or strain 2 guinea pigs. The LSLC were subsequently isolated by collagenase digestion and density separation and assessed for the ability to induce proliferation of antigen-primed accessory cell-depleted syngeneic peritoneal exudate T lymphocytes in vitro. The in vivo antigen-pulsed LSLC were found to present antigen in vitro to primed T cells in an antigen-specific and genetically restricted manner. T cell DNA synthesis induced by antigen-bearing LSLC could be augmented by coculture with additional accessory cells, but not IL 1-containing macrophage supernatants. Enhancement of responsiveness was not genetically restricted. The demonstration that LSLC can take up, process, and retain antigen in vivo and present it to primed T cells in vitro suggests that LSLC are capable of contributing to the immune response to antigens appearing in portal blood.

Animals↗
PubMed1986

Liver sinusoidal lining cells express class II major histocompatibility antigens but are poor stimulators of fresh allogeneic T lymphocytes.

Guinea pig liver sinusoidal lining cells (LSLC), a mixture of Kupffer cells (KC) and sinusoidal endothelial cells (EC), were examined for their capacity to function as antigen-presenting cells (APC). LSLC were extremely poor stimulators of freshly isolated allogeneic T lymphocytes even though a large number of them expressed class II major histocompatibility complex (MHC) antigens (Ia). This deficiency could not be explained by a lack of soluble factor production by LSLC, because an interleukin 1-containing macrophage (M phi) supernatant could not restore the capacity of LSLC to stimulate allogeneic T cells. Moreover, LSLC were able to promote mitogen-induced proliferation of accessory cell-depleted T lymphocytes. No evidence of suppression was apparent in experiments in which LSLC were added to cultures of T cells stimulated by allogeneic peritoneal exudate M phi (PEM). The Ia expressed by LSLC was functional because they were able to stimulate an alloreactive T cell line. When LSLC were mixed and co-cultured with either PEM syngeneic to the responding lymphocytes or Ia-negative fibroblasts, the allostimulatory ability of LSLC was greatly augmented. In contrast, the addition of mitogen-activated T cell supernatants had only a minimal effect on the capacity of LSLC to stimulate allogeneic T cells. The data suggest that LSLC lack a biologic property that is necessary for recognition of class II MHC determinants by fresh but not primed allogeneic T cells and that is not required to support T cell activation induced by nonspecific mitogenic lectins. These findings may be important in understanding the reason that antigen introduced into the portal blood appears not to initiate an immune response.

Animals↗
PubMed1985

Double blind comparative study of omeprazole 10 mg and 30 mg daily for healing duodenal ulcers.

Healing of duodenal ulcers was assessed in 66 patients who received omeprazole either 10 mg or 30 mg daily for four weeks in a double blind study. Healing was rapid in both groups. At two weeks the ulcers in 15 of the 30 patients taking 10 mg daily had healed compared with 28 of the 36 (78%) taking 30 mg daily (p less than 0.03). At four weeks the respective proportions had risen to 83% (25/30) and 94% (33/35) (p greater than 0.05). In non-smokers the proportion of ulcers healed did not differ significantly with the two doses, although there was a trend for less healing at two weeks with 10 mg daily; in smokers significantly fewer ulcers (p less than 0.05) were healed with 10 mg than 30 mg daily at two weeks (7/16 (44%) v 17/21 (81%] and at four weeks (12/16 (75%) v all 21 (100%]. Adverse reactions were few and transient and were considered unlikely to be due to omeprazole.

Adult↗
PubMed1985

Hepatic hydrothorax in the absence of clinical ascites: diagnosis and management.

Two cases of right hepatic hydrothorax occurring in the absence of clinical ascites are reported. Diagnosis was confirmed by the intraperitoneal and intrapleural injection of radioisotope 99mTc-sulfur colloid that demonstrated the one-way transdiaphragmatic flow of fluid from the peritoneal to pleural cavities. In contrast, radioisotope injected into the peritoneal cavity of 5 patients with pleural effusions secondary to pulmonary or cardiac disease failed to traverse the diaphragm and localize in the pleural space. Medical therapy with salt and water restriction and diuretics resulted in both of the patients with hepatic hydrothorax developing signs of intravascular volume depletion without significant mobilization of the pleural fluid. Thoracotomy allowed identification of the diaphragmatic defects that were repaired by chemical and traumatic pleurodesis followed by postoperative peritoneal and pleural drainage. This therapy resulted in complete resolution of the pleural effusions, which have not recurred despite the subsequent development of clinical ascites in both patients.

Ascitic Fluid↗
PubMed1985

Morbidity and mortality after peritoneovenous shunt surgery for refractory ascites.

A prospective analysis of the morbidity and mortality after peritoneovenous shunting was carried out in 25 patients who had a total of 27 shunts for refractory ascites. Major complications were limited to the patients in whom ascites was secondary to hepatic rather than peritoneal disease. Immediate postoperative complications followed 17 out of the 23 shunts carried out in patients with liver disease and included septicaemia (two), profound hypotension (two), pulmonary oedema (one), and clinically evident disseminated intravascular coagulation (14). Long term morbidity was again limited to the patients with liver disease and included chronic shunt infection (two) and major venous thrombosis (two). Shunt associated mortality was only seen in the patients with liver disease. Despite late shunt blockage in five long term survivors with alcoholic liver disease fluid retention was easily controlled by simple medical means probably because of improved liver function associated with abstinence from alcohol. It is concluded that: (1) patients with hepatic and malignant ascites respond differently to the insertion of a peritoneovenous shunt; (2) Shunt patency should be monitored regularly in patients with liver disease and, because of the potential for septic and thrombotic complications, if blocked the shunt should be removed and; (3) because of the morbidity and mortality of peritoneovenous shunt surgery in patients with liver disease and refractory ascites, an alternative mode of therapy, such as repeated ultrafiltration and reinfusion of ascitic fluid, may be a more effective initial therapeutic approach especially in patients in whom there is a reversible element to their underlying liver disease.

Ascites↗
PubMed1981

Exchange of phosphatidylcholine between rabbit erythrocytes and plasma in vivo.

Phosphatidylcholine exchange between rabbit erythrocytes and plasma was studied in vivo. The erythrocyte phosphatidylcholine was labeled by exchange in vivo with [32P] phosphatidylcholine and in vitro by acylation with [3H] 16:0 and [14C] 18:2. The erythrocytes were then injected into rabbits and the loss of labeled phosphatidylcholine from the cells by exchange was followed. The rate constants for the exchange of [32P]-, [3H] 16:0-, and [14C] 18:2-phosphatidylcholine were .013 +/- .0010, .0093 +/- .0014 and .0074 +/- .0013 h-1, and the exchange rates of the labels relative to that of [32P] were 1.0, 0.71 +/- .16, and 0.56 +/- .14, respectively. These results confirm our earlier in vitro findings and represent the first in vivo demonstration of the dependency of the exchange rate of erythrocyte phosphatdylcholines on their metabolic prehistory.

Animals↗
PubMed1981

Uptake of cholesterol from the very low density lipoprotein or its remnants by the perfused rat liver.

[3H]Cholesterol labelled very low density lipoproteins ([3H]chol-VLDL) were prepared to study the hepatic uptake of cholesterol associated with VLDL and its remnants in the perfused liver system. [3H]Chol-VLDL was incubated with rat postheparin plasma to produce labelled remnants in vitro. The degree of lipolysis of [3H]chol-VLDL depended on the ratio of triacylglycerols to lipase in the incubation medium. Therefore, the produced remnant of d less than 1.019 g. mL-1 had a variable lipid composition depending on the degree of lipolysis. [3H]Chol-VLDL or its remnants were added to liver perfusate and the radioactivity remaining in the perfusate was measured. The kinetic disappearance of [3H]chol-VLDL and its remnants in the perfused liver system indicated that remnant of d less than 1.019 g. mL-1 was taken up by the liver faster than the original VLDL preparation (t1/2 of 8 min vs. 51 min). Appearance of the label in bile during the perfusion was significantly faster when livers were perfused with [3H]chol-VLDL remnants as opposed to uncatabolized [3H]chol-VLDL. The results indicate that first of all, VLDL remnants produced in vitro and reisolated at density less than 1.019 g.mL-1 do not have a fixed lipid composition but a rather variable one depending on the degree of lipolysis. Secondly, the rat liver may preferentially recognize this VLDL remnant of d less than 1.019 g.mL-1 and take it up more readily than uncatabolized VLDL. Finally when equimolar amount of cholesterol from VLDL or VLDL remnants are circulated in the liver perfusion, the VLDL remnants convey a significantly greater mass of cholesterol in the bile.

Animals↗