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Biomedical subjects

M Ritz

Publications and source records attributed to M Ritz.

At least 37 records · Page 2Linked to original sources
PubMed1996

Human immunodeficiency virus infection in an emergency hand service.

A study prompted by the high number of human immunodeficiency virus (HIV) patients in the South African population was performed to evaluate the incidence of HIV in patients attending our Emergency Hand Service. Over a 6-month period, more than 500 consecutive emergency patients were tested for HIV. In our series, 24 patients tested HIV-positive. Of these, 14 presented with hand sepsis and 10 with hand injuries. Bacteriology was performed on all patients with sepsis to document bacteria type and sensitivity. CD4 counts (T4 lymphocyte counts) were done on 12 patients to assess immunocompetence. Other factors examined included hospital stay, number of operations, postoperative morbidity, and mechanism of injury. Results indicate that septic HIV patients spent more time in the hospital and required more operations than septic non-HIV patients. Furthermore, of all of the population of emergency hand patients, a larger percentage of HIV-positive persons than HIV-negative persons was likely to be seen for infection.

Adult↗
PubMed1994

[Electrostimulation of nerve roots in neurogenic bladder].

Thirty per cent of the patients with spinal injuries present chronical urinary problems. For these, G.S. Brindley's technique represents an important progress. It includes a section of posterior roots to control detrusor hyperexcitability and a stimulation of anterior roots to empty the bladder. The equipment is now perfectly reliable and the technique has been defined. Indications are essentially unstable bladders with incontinence and certain hypoactive bladders. The following results were obtained: continence is obtained in 90% of patients; complete bladder emptying in the majority of cases with very marked reduction of urinary infections; improvement of erection and regularization of intestinal transit. The complications of the surgery are uncommon but serious (CSF leaks, postoperative denervations, sepsis and material failure).

Electric Stimulation Therapy↗
PubMed1994

Drug mixture which improves survival of ischemic rabbit epigastric skin flaps.

The chief aim of this study was to maximize flap survival by counteracting the pathophysiological changes occurring during ischemia-reperfusion. Rabbit epigastric skin flaps given 21 hours of ischemia were infused intra-arterially with selected drugs at the start of reperfusion. Compared with control infused ischemic flaps, which had a 33% survival rate on day 7 post-ischemia, significant improvement was found with vasodilators nitrendipine (61%) and prostacyclin (65%) and the thrombolytic agent urokinase (65%); marginal improvement with the free radical scavenger desferrioxamine (53%); but no change with streptokinase (44%), heparin (21%), and ATP-MgCl2 (35%). A drug mixture comprising all of these agents except streptokinase and urokinase produced 87% survival, suggesting an additive effect. Biochemical assays on skin homogenates and blood implicated oxygen free radicals, neutrophil infiltration, and thromboxane in flap failure. These results imply that multiple factors are responsible for ischemic flap failure and that a mixture of drugs needs to be infused to counteract all of the detrimental changes.

Adenosine Triphosphate↗
PubMed1994

Flushing the vessel ends: the effect on ischemic free flap survival.

During vascular anastomosis of experimental ischemic free flaps it is common to observe that stagnant blood in the vessel ends has clotted. A study was performed to investigate if flushing away the stagnant blood on division of the vessels would increase flap survival. Flushing did not influence flap survival. Clinically, clot is rarely seen, except in conditions of prolonged ischemia or damaged vessels. Current surgical practice does not involve flushing the vessel ends upon division of the vessels and this approach is affirmed by our results.

Anastomosis, Surgical↗
PubMed1994

Glycosaminoglycan composition of uninjured skin and of scar tissue in fetal, newborn and adult sheep.

Few details are available on the heterogeneity of glycosaminoglycans (GAGs) in healing fetal wound tissue. We used a sensitive assay for hexosamines to examine changes occurring in the development of normal sheep skin and of wound healing tissue in PVA sponges inserted subcutaneously at different stages of gestation. It was assumed that glucosamine was derived mainly from hyaluronan and galactosamine mainly from dermatan sulphate and chondroitin sulphate. Hexosamine-containing tissue infiltrating the sponges was deposited more rapidly in the first week than in the second week. Three days after wounding, approximately 70% of the total GAGs in wound tissue was hyaluronan. The proportion of hyaluronan then fell progressively and by the 14th day contributed 57% to the total GAGs. In uninjured skin the contribution of hyaluronan to the total GAGs fell progressively with increasing fetal maturity, the level being 70% at 75 days gestation, but only 35-40% in newborn or adult skin. At no stage of development was there a sudden change in GAG composition suggestive of a transition from regeneration to scar formation. It is concluded that hyaluronan may play an important role in the biochemical sequence leading to collagen fibrillogenesis and mature scar formation.

Animals↗
PubMed1994

Acute inflammation in foetal and adult sheep: the response to subcutaneous injection of turpentine and carrageenan.

Because of the small number of inflammatory cells found in skin wounds, it has been considered that foetal sheep are incapable of an adequate inflammatory response. The present study shows that subcutaneous injection of turpentine or carrageenan into foetal sheep consistently excites a severe cellular inflammatory reaction. At 75 days gestation the inflammatory cells are all macrophages. As the foetus develops, polymorphs play an increasing role in the early response to turpentine. By 120 days inflammatory cells are almost all polymorphs as in adult sheep. However the response to carrageenan remains macrophage in type. At all stages of gestation the acute cellular response is followed by development of scar tissue, more pronounced with turpentine than carrageenan. Any proposed intrauterine surgery must allow for the pronounced and prolonged inflammatory response and scar tissue formation caused by persistent inflammatory stimuli in foetal animals.

Animals↗
PubMed1994

Autologous lymphocyte therapy for experimental canine lymphoedema: a pilot study.

Obstructive lymphoedema, an accumulation of protein-rich fluid in interstitial spaces, was created in five dogs by a combination of the irradiation of one groin and subsequent surgical ablation of any remaining lymphatics. The lymphoedema was stable for up to 2 years. The aim was to test the efficacy of intra-arterial injection of autologous lymphocytes as a therapy for lymphoedema. The hypothesis was that cytokines produced by lymphocytes mediate proteolysis by macrophage proteinases in the lymphoedematous limb to remove the excess protein and relieve the oedema. A concentrated lymphocyte-rich preparation was isolated from blood by the Ficoll-Paque method. These preparations were injected into the femoral artery four times at approximately 4 weekly intervals. Three months after the first injection of lymphocytes, lymphoedematous limbs showed a marked 69% reduction in the mean excess circumferences compared with opposite control limbs. After treatment, skin thickness and hydroxyproline content (both measures of fibrosis) as well as water content (a measure of oedema) had reduced significantly. In specimens of interstitial fluid and in skin homogenates acidic proteinase activity increased and the protein concentration decreased significantly compared with controls. It is concluded that increased proteolysis, possibly due to activated macrophages recruited to the lymphoedematous limb, may partly explain these results.

Animals↗
PubMed1994

Multiple-dose pharmacokinetics of sparfloxacin and its influence on fecal flora.

In a randomized, double-blind, placebo-controlled, multiple-dose pharmacokinetic study, the safety and effect on intestinal flora of sparfloxacin (SPX) were determined in 12 healthy male volunteers (8 received SPX and 4 received a placebo). Following fasting and oral administration of 400 mg on day 1 and 200 mg on days 2 to 8, concentrations of the free drug in serum, urine, and feces were measured by high-performance liquid chromatography; serum and urine were also evaluated by a microbiological assay. All results, except those for renal excretion, exclude the glucuroconjugate metabolite. A mean peak concentration in serum (400-mg dose) of 0.56 +/- 0.13 mg/liter was measured 3.52 +/- 0.98 h after administration. Pharmacokinetic parameters (measured by high-performance liquid chromatography) were based on an open, one-compartment model and resulted in the following day 1 (calculated for the 200-mg dose), day 4 (recalculated for a single dose), and day 8 values (mean +/- standard deviation): area under the curve, 16.4 +/- 2.3 (day 1) and 18.3 +/- 5.1 (day 4) mg.h/liter; elimination half-life, 18.3 +/- 3.9 h; steady-state volume of distribution, 4.7 +/- 1.4 (day 1) and 4.3 +/- 1.2 (day 8) liters/kg; apparent total clearance, 201 +/- 31 (day 1) and 190 +/- 51 (day 4) ml/min; renal clearance, 19.1 +/- 5.8 (day 1) and 23.2 +/- 19.4 (day 4) ml/min. Recovery in urine on day 1 was 5.89% +/- 1.4% of the dose in 24 h for the parent compound and 18.4% +/- 6.8% for the SPX glucuronide.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Non-therapeutic operations for penetrating trauma: early morbidity and mortality.

A prospective study was carried out to assess the incidence and type of complications after non-therapeutic operations for penetrating trauma. A total of 372 operations were performed on 368 patients with penetrating injuries to the abdomen (240 procedures), chest (49), neck (48) and extremities (35). There were 46 negative or non-therapeutic operations. The incidence of major complications directly related to anaesthesia or operation in this group of patients was 4 percent (two patients). The operation might have contributed to a further three major complications. The mean hospital stay for patients undergoing uncomplicated non-therapeutic operation was 4.1 days; for those with complications it was 21.2 days. It is concluded that non-therapeutic operations for penetrating trauma carry a significant morbidity rate. A policy of selective conservatism is advocated.

Abdominal Injuries↗
PubMed1993

Infusions of a novel calcitonin gene-related peptide (CGRP) derivative at the time of reperfusion to salvage ischaemic rabbit skin flaps.

Rabbit epigastric skin flaps were subjected to 21 h of ischaemia at 25 degrees C. In the first 40 min of reperfusion the flaps were infused intraarterially with either Hanks' balanced salt solution (controls), chicken CGRP or a derivative DADA-CGRP. Skin biopsies and blood specimens were taken immediately before and after 1-h reperfusion. The aim was to observe the effect of CGRP derivatives on compromised skin-flap survival and to help elucidate the critical biochemical mechanisms. It was found that chicken CGRP and DADA-CGRP produced a dose-dependent increase in blood flow, significant at and above 0.1 microgram/kg, but only the 0.1 microgram/kg DADA-CGRP infusion produced a statistically significant increase in flap survival (75.1%) as compared with controls (41.6%). CGRP infusions caused significantly more rapid restoration of tissue ATP levels and resulted in a smaller rise in blood thromboxane as compared with controls. However, CGRP caused no significant change in the tissue levels of myeloperoxidase, a measure of neutrophil infiltration, and lipid peroxidation, an indicator of free-radical activity. It is concluded that intraarterial CGRP infusions to ischaemic flaps at the time of reperfusion are indicated. However, an ideal infusion solution would also need to counteract free radicals and neutrophils which are believed to also play a major role in the inflammatory response leading to flap failure.

Animals↗
PubMed1993

Collagen content of uninjured skin and scar tissue in foetal and adult sheep.

Total collagen content (measured as hydroxyproline) and Type I/Type III ratio (measured by SDS-PAGE) of normal skin and of scar tissue developing within a subcutaneously implanted polyvinyl sponge have been determined in 75, 90 and 120-day foetal lambs and adult sheep and correlated with histological appearances of the same tissues. Collagen content of normal skin is low at 75 days and rises progressively until birth when it is about half the adult level. The proportion of Type III in normal skin is highest at 75 days and falls progressively as the foetus develops. With implanted sponges the time course of changes in collagen content and I/III ratio are similar in all foetal groups and in adult sheep. Collagen content is low 3 days after implantation and rises progressively to reach a similar level in all groups by 28 days. The levels correlate closely with the amount of collagen visible in histological sections. The proportion of Type III is highest at 3 days in all groups and falls progressively as the newly formed tissue matures. The findings confirm our previous study of the healing of skin wounds that form as early as 75 days gestation foetal lambs can form scar tissue in a similar way to adult sheep.

Animals↗
PubMed1993

[Electrostimulation of anterior sacral nerve roots in the treatment of central neurogenic bladders. G.S. Brindley's technique. Results of the 40 first French cases].

The results of the first 40 cases who underwent implantation of a sacral anterior root stimulator (G.S. Brindley) in France are reported. One patient die two years after implantation from an unrelated cause. 39 patients are using electrostimulation with a 6 month to 8 year follow-up. 90% have a satisfactory continence and no longer require an incontinence appliance. 82% of the patients have a post-void residue of 0 to 50 cc. Urinary infection rate has dramatically decreased. Bladder capacity and compliance have increased, and urethral closure pressure has decreased according to posterior rhizotomy. Possible side effect of total posterior rhizotomy from S2 to S4 could be stress incontinence.

Adult↗
PubMed1992

Wound healing in foetal sheep: a histological and electron microscope study.

A study was made of the healing of excised, unsutured and sutured skin wounds in foetal sheep of 75, 90 and 120 days gestation and of wounds in newborn lambs and adult ewes. Foetal and postnatal wounds were found to heal in a very similar way. At each stage of development studied, excised wounds contract rapidly and histological and electron microscope examination demonstrates formation of granulation tissue and its maturation to scar tissue in all types of wound. Examination of polyvinyl sponges 7 and 14 days after subcutaneous implantation confirms the ability of foetal sheep to form vascularised scar tissue. The cellular inflammatory response to wounding is much less prominent in foetal than in postnatal sheep, the number and type of extravascular cells reflecting the changes in blood leucocyte content during development. From a very early stage foetal sheep react to insoluble irritants by the formation of multinucleate giant cells.

Actins↗
PubMed1989

Effects of Aroclor 1254 on dopamine and norepinephrine concentrations in pheochromocytoma (PC-12) cells.

Pheochromocytoma (PC-12) cells synthesize, store, release and metabolize dopamine (DA) and norepinephrine (NE) in a manner analogous to that observed in the mammalian central nervous system. These cells were used to develop and validate an alternate method to animal testing to assess the effects of a complex environmental mixture of polychlorinated biphenyls (Aroclor 1254) on cellular catecholamine function. Aroclor 1254, at concentrations of 1 to 100 ppm, significantly decreased cellular catecholamine concentrations after 6 hrs. Exposure at 100 ppm for periods of less than an hr increased cellular catecholamine concentrations while longer exposure times (i.e., 1 to 24 hr) decreased cellular catecholamine concentrations. This in vitro depletion of catecholamines is similar to that seen in vivo. Thus, PC-12 cells may be useful for neurochemical evaluation of neurotoxicants with particular reference to effects on catecholaminergic systems.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

A new approach for the refinement of the very broad nasal tip.

Refining the very broad nasal tip has been difficult to achieve with a single technique. Operations described often violate the domes and may result in visible irregularities and collapse of the ala. Adequate narrowing can be obtained by decreasing the angle between medial and lateral crura of the ala cartilage at the dome and decreasing the overall length of the ala cartilage. This narrowing is achieved predictably by removing a small segment at the lateral most part of the ala cartilage. Scoring of the dome can also be done. We describe the technique in a large series of patients, all of whom have retained their results without undesirable problems.

Cartilage↗