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Biomedical subjects

S Roth

Publications and source records attributed to S Roth.

At least 163 records · Page 9Linked to original sources
PubMed1996

The soft tissue cover of the mandibular condyle: age-related changes in high buoyant density proteoglycans, free tissue water and remodelling activity.

Age-related changes in the relative proportion of high buoyant density proteoglycans of the soft tissue cover of the mandibular condyle of domestic pigs and the chemical composition of these proteoglycans were investigated by biochemical methods. The relative proportion of high buoyant density proteoglycans has been shown to decrease with age, with their chemical composition varying as follows: With age, the relative proportions of protein increased, galactosamine decreased, glucosamine was similar in newborns and juveniles, but clearly increased in adults, galactosamine plus glucosamine decreased. As measured by 1H-NMR-relaxation spectroscopic methods, the concentration of free tissue water of the soft tissue cover of the mandibular condyle decreased with age. Its mobility, however, was greater in newborns than in juveniles, but similar in juveniles and adults. The concentration of free tissue water, but not its mobility, correlated weakly with relative proportions of polyanionic side chains (e.g. chondroitin sulphate plus keratan sulphate chains) of the high buoyant density proteoglycans. By affecting the concentration of free tissue water and in turn of matrix solutes and cellular environments, the high buoyant density proteoglycans of the soft tissue cover of the mandibular condyle seem to be involved in regulation of age-related changes in the adaptive remodelling activity of the mandibular condyle.

Aging↗
PubMed1996

[The perioperative use of recombinant erythropoietin (rhEPO) in Jehovah's witnesses].

UNLABELLED: Erythropoietin, the hematopoietic growth factor, is synthesised in the kidneys and liver and regulates red blood cell production. Within the last few years, recombinant DNA technology has produced synthetic erythropoietin (rhEPO). Some patients, especially Jehovah's Witnesses, will not accept blood transfusion. The perioperative administration of rhEPO increases the patients' hematocrit (HCt) to a higher than physiological level. METHODS AND RESULTS: We report a case of a 66-year-old female Jehovah's Witness who refused blood transfusions and responded favourably to rhEPO treatment. A total hip arthroplasty was planned. A pretreatment hemoglobin level (Hb) of 13.7 g/dl and HCt of 43% were documented. After preoperative subcutaneous application of 5000 I.E. rhEPO three times per week and daily oral substitution of 300 mg ferrous sulfate over a period of 3 weeks, the Hb increased to 15.5 g/dl and the HCt to 49%. The operation was carried out after the ninth application of rhEPO. Postoperatively, the Hb concentration was 11.8 g/dl and the HCt 35%. Therefore, postoperative administration of rhEPO was not considered indicated. No side effects of rhEPO application were noted. The patient left hospital on the 10th postoperative day. CONCLUSIONS: The case report describes perioperative management using human rhEPO in Jehovah's Witnesses. Treatment with rhEPO increases preoperative Hb levels to a point making it possible to compensate for operative blood loss. RhEPO combined with daily iron substitution may be useful in patients who refuse transfusion based on religious convictions.

Aged↗
PubMed1996

Nitric oxide: a review of its role in retinal function and disease.

Nitric oxide synthase (NOS), the enzyme that catalyzes the formation of nitric oxide from L-arginine, exists in three major isoforms, neuronal, endothelial, and immunologic. Neuronal and endothelial isoforms are constitutively expressed, and require calcium for activation. Both of these isoforms can be induced (i.e., new protein synthesis occurs) under appropriate conditions. The immunologic isoform is not constitutively expressed, and requires induction usually by immunologic activation; calcium is not necessary for its activation. Neuronal and immunologic NOS have been detected in the retina. Neuronal NOS may be responsible for producing nitric oxide in photoreceptors and bipolar cells. Nitric oxide stimulates guanylate cyclase of photoreceptor rod cells and increases calcium channel currents. In the retina of cats, NOS inhibition impairs phototransduction as assessed by the electroretinogram. Inducible nitric oxide synthase, found in Müller cells and in retinal pigment epithelium, may be involved in normal phagocytosis of the retinal outer segment, in infectious and ischemic processes, and in the pathogenesis of diabetic retinopathy. Nitric oxide contributes to basal tone in the retinal circulation. To date, findings are conflicting with respect to its role in retinal autoregulation. During glucose and oxygen deprivation, nitric oxide may increase blood flow and prevent platelet aggregation, but it may also mediate the toxic effects of excitatory amino acid release. This reactive, short-lived gas is involved in diverse processes within the retina, and its significance continues to be actively studied.

Animals↗
PubMed1996

Measurement of purine nucleoside concentration in the intact rat retina.

Adenosine, produced from the decomposition of adenosine triphosphate, is believed to provide protective effects during ischemia. On the other hand, adenosine metabolites may serve as precursors for oxygen free radical formation. These substances have not been previously measured in intact vertebrate retina, where adenosine and its metabolites may play a role in the pathogenesis of ischemic injury. The small tissue mass of the retina, particularly in rats, renders these measurements challenging. Furthermore, accurate measurement of purine nucleosides requires immediate cessation of ongoing adenosine metabolism. Concentrations of adenosine and its purine nucleoside metabolites inosine, hypoxanthine, and xanthine in the retina of ketamine/xylazine-anesthetized rats were measured after in situ freezing using high-performance liquid chromatography. The retina was removed from the frozen eyes and analyzed. Quantitative measurements were made possible through the use of an internal standard. Ischemia was induced by ligation of the central retinal artery. Retinal purine nucleoside concentrations did not differ between the two eyes of the rat under control conditions, and there was no effect of placement of the ligating suture itself compared to completely unmanipulated eyes. Use of two different in situ freezing methods yielded comparable results. To evaluate the impact of a period of ischemia, one retina of each rat was ischemic for 30 min, and the other, non-ischemic. Our measurements were associated with a high degree of reproducibility and minimal variability, and significant changes in purine nucleoside concentrations were detectable in the retina after 30 min of ischemia. Our method may be used to assess the role of adenosine and its metabolites in the pathogenesis of ischemic neuronal injury, including in the retina.

Animals↗
PubMed1996

Red blood cell polyamines, anaemia and tumour growth in the rat.

In rats with Mat Lylu prostatic carcinoma, significant changes in blood composition and red blood cell (RBC) characteristics were observed. Anaemia, characterised by a decrease in the number of RBC and the reduction of haemoglobin and the iron content in plasma, was correlated with tumour size and the accumulation of spermidine and spermine in the RBC. In large tumours, spermidine levels were increased by 8-fold over normal value. Spleen weight and splenic spermidine concentrations were enhanced in animals with tumours. After splenectomy, the rate of tumour growth decreased by 30%. It is proposed that anaemia in tumour-bearing animals is caused by enhanced RBC lysis, owing to the alteration of the rheological properties of RBC. These may be caused by the alterated surface characteristics due to polyamine accumulation. RBC lysis and high concentrations of polyamines in RBC and spleen appear, not only to favour tumour growth, but also to compromise the immunological defence mechanisms against neoplastic invasion.

Anemia↗
PubMed1996

Eye injuries after nonocular surgery. A study of 60,965 anesthetics from 1988 to 1992.

BACKGROUND: Eye injuries after anesthesia, although infrequent, may result in visual impairment. Previous studies have not defined the risk factors associated with these injuries. To study the cause of these injuries and to determine incidence data, the authors reviewed the records from a 4.5-y period of patients who sustained eye injuries after anesthesia and nonocular surgery. METHODS: The records were surveyed of 60,965 patients who underwent anesthesia for nonocular surgery at our institution from January 1988 to July 1992. Eye injuries were identified by examining several sources of information, including quality improvement data, postoperative visits or telephone calls, and examination of medical records of postoperative patients who required an ophthalmology consultation. Records were reviewed to determine the types and causes of eye injuries. Logistic regression, with univariate and multivariate analysis, was used to identify the importance of possible risk factors. RESULTS: Of 34 patients who sustained eye injuries (0.056%), the most common was corneal abrasion (n = 21). Other injuries were conjunctivitis, blurred vision, red eye, chemical injury, direct trauma, and blindness. Independent factors associated with a higher relative risk of eye injury were long surgical procedures (odds ratio, 1.16 per hour of anesthetic care; CI, 1.1 to 1.3), lateral positioning during surgery (odds ratio, 4.7; CI, 2 to 11), operation on the head or neck (odds ratio, 4.4; CI, 2.2 to 9.0), general anesthesia (odds ratio, 3.0; CI, 2.2 to 38), and surgery on a Monday (odds ratio, 2.7; CI, 1.4 to 5.3). In only 21% of cases was a specific cause of injury identified. CONCLUSIONS: For reasons not understood, eye injuries are more common in patients who are older or who undergo lengthier procedures. The cause of injury was usually not determined by the authors' methods. Until the mechanisms producing perioperative eye injuries are better understood, it is difficult to identify strategies to prevent this type of injury.

Adult↗
PubMed1996

Dissociation, somatization, and affect dysregulation: the complexity of adaptation of trauma.

OBJECTIVE: A century of clinical research has noted a range of trauma-related psychological problems that are not captured in the DSM-IV framework of posttraumatic stress disorder (PTSD). This study investigated the relationships between exposure to extreme stress, the emergence of PTSD, and symptoms traditionally associated with "hysteria," which can be understood as problems with stimulus discrimination, self-regulation, and cognitive integration of experience. METHOD: The DSM-IV field trial for PTSD studied 395 traumatized treatment-seeking subjects and 125 non-treatment-seeking subjects who had also been exposed to traumatic experiences. Data on age at onset, the nature of the trauma, PTSD, dissociation, somatization, and affect dysregulation were collected. RESULTS: PTSD, dissociation, somatization, and affect dysregulation were highly interrelated. The subjects meeting the criteria for lifetime (but not current) PTSD scored significantly lower on these disorders than those with current PTSD, but significantly higher than those who never had PTSD. Subjects who developed PTSD after interpersonal trauma as adults had significantly fewer symptoms than those with childhood trauma, but significantly more than victims of disasters. CONCLUSIONS: PTSD, dissociation, somatization, and affect dysregulation represent a spectrum of adaptations to trauma. They often occur together, but traumatized individuals may suffer from various combinations of symptoms over time. In treating these patients, it is critical to attend to the relative contributions of loss of stimulus discrimination, self-regulation, and cognitive integration of experience to overall impairment and provide systematic treatment that addresses both unbidden intrusive recollections and these other symptoms associated with having been overwhelmed by exposure to traumatic experiences.

Adaptation, Psychological↗
PubMed1996

Modified ureteral stripping as an alternative to open surgical ureterectomy.

PURPOSE: Using a compression technique instead of the classical invagination technique in cases of total nephroureterectomy improves traction during transurethral stripping of the ureteral stump. MATERIALS AND METHODS: Eight patients underwent our modified compression technique. After nephrectomy a kinked 5F ureteral catheter is attached to the ureteral stump with a double ligation. Traction on the ureteral catheter is used to achieve ureteral compression. RESULTS: There were no intraoperative difficulties except for 1 dislodged ureteral catheter. No complications were associated with ureteral detachment or resection. CONCLUSION: Our technique offers an alternative to the classic invagination technique by increasing transurethral traction on the ureteral stump, while substantially decreasing the risk of ureteral catheter dislodgment.

Humans↗
PubMed1996

Simplified uretero-intestinal implantation in continent cutaneous urinary diversion using ileovalvular segment as afferent loop and appendix as continent outlet.

PURPOSE: We performed continent cutaneous urinary diversion with implantation of ureters as in ileal loop diversion to reduce the risk of ureterointestinal implantation stricture. MATERIALS AND METHODS: Four patients underwent colonic pouch and 11 underwent ileocecal continent urinary diversion the ileocecal segment used as an afferent loop and the sphincter-like function of the ileocecal valve used as an antireflux mechanism. RESULTS: All preoperatively undilated renal units (26 of 30) remained postoperatively undilated. Of the 4 preoperatively dilated renal units 3 also showed postoperatively improvement (mean followup 8 months). However, after 3 to 14 months transient reflux occurred during contraction waves in the reservoir in 6 renal units. CONCLUSIONS: Our modified technique simplifies ureteral reimplantation and appears to diminish the postoperative complication of anastomotic structure. The solution to the problem of occasional reflux may be reinforcement of the ileocecal valve.

Adult↗