Hypotensive and bradycardiac responses to reflex sympathetic inhibition produced by nitroglycerin in rats with sinoaortic deafferentation

Nitroglycerin (NTG) may cause paradoxical bradycardia and occasional life-threatening hypotension. The mechanism is unclear. In this study, we compared the cardiovascular responses of sodium nitroprusside (SNP) with that of NTG in rats with sinoaortic deafferentation (SAD). Intravenous (i.v.) injection of SNP and NTG produced dose-dependent decreases in mean arterial pressure (MAP). SNP was more effective than NTG in increasing heart rate (HR). After SAD, tachycardiac responses to i.v. SNP were abolished, but i.v. NTG caused bradycardia. SAD enhanced the hypotensive responses of both NTG or SNP after i.v. administration. The bradycardic and hypotensive effects of NTG were attenuated by either bilateral vagotomy or intracisternal (i.c.) pretreatment with 20 nmol rauwolscine, but the responses were not altered by i.v. atropine methylbromide (M-atropine), 0.6 mumol. In contrast, cardiovascular responses to i.v. SNP after SAD were not altered by these pretreatments. Tachycardiac responses to intracerebroventricular (i.c.v.) injection of NTG were reduced by SAD, but SAD did not alter bradycardic responses to i.c. injection of NTG. These results suggest that NTG induces inhibitory reflexes that may contribute to its complex cardiovascular responses in rats. The drug may stimulate peripheral sensory receptors with vagal afferents to the medulla, which then triggers an alpha 2-adrenoceptor-mediated sympathoinhibition.

Initiation of bone regeneration in adult baboons by osteogenin, a bone morphogenetic protein

Osteogenin, and related bone morphogenetic proteins, induce endochondral bone differentiation through a cascade of events which include formation of cartilage, hypertrophy and calcification of the cartilage, vascular invasion, differentiation of osteoblasts, and formation of bone. These events have been studied in a postnatal model of bone development in rodents. Information concerning the morphogenetic potential of osteogenin in primates is a prerequisite for potential clinical application in man. The efficacy of allogeneic osteogenin in primates was investigated in both extraskeletal and skeletal sites in 19-Chacma baboons (Papio ursinus). Osteogenin was isolated from demineralized baboon bone matrix and purified by chromatography on heparin-Sepharose, hydroxyapatite, and Sephacryl S-200. Protein fractions with a molecular mass range of 26-42 kDa induced cartilage and bone differentiation in the subcutaneous space of rats. Final purification to homogeneity was obtained by electroendosmotic elution from a preparative sodium dodecyl sulphate (SDS) polyacrylamide gel, resulting in a single band on a SDS-polyacrylamide gel with an apparent molecular mass of 30-34 kDa, with biological activity in rats. The osteoinductive potential of osteogenin in primates was tested first in intramuscular sites in baboons and found to be active. The bone regeneration potential was investigated in nonhealing calvarial defects surgically prepared in adult male baboons. Baboon osteogenin induced complete regeneration of the cranial wound. These findings in adult primates establish a primary role for osteogenin in initiation and promotion of osteogenesis, and imply a potential therapeutic application based on cell biology of extracellular matrix-cell interactions.

The critical role of geometry of porous hydroxyapatite delivery system in induction of bone by osteogenin, a bone morphogenetic protein

The collagenous extracellular matrix of bone obtained after dissociative extraction with 4 M guanidine-HCl is an optimal substratum for bone induction by osteogenin, a bone morphogenetic protein. As a proteinaceous substratum, this matrix and other collagen-based materials may be immunogenic. Thus, the search and discovery of a non-immunogenic substratum is a necessary prerequisite for the therapeutic application of the principle of bone induction to skeletal repair. Bovine osteogenin, purified greater than 50,000-fold and with an apparent molecular mass of 28-42 kilodaltons, was delivered into nonresorbable porous hydroxyapatite in granular and disc configuration. A total of 328 preparations were bioassayed for osteogenic activity by subcutaneous implantation into 164 Long-Evans rats. Specimens were harvested at day 7, 11 and 21 after implantation and subjected to alkaline phosphatase activity determination and histologic analysis. Osteogenin combined with discs of porous hydroxyapatite induced in vivo differentiation of the osteogenic phenotype in mesenchymal cells invading the three-dimensional porous space of the inorganic substratum. The geometry of the substratum had a profound influence on bone induction, since the expression of the osteogenic phenotype was solely confined in porous hydroxyapatite with disc configuration. Osteogenin did not induce bone differentiation when combined with granules of porous hydroxyapatite with identical pore dimensions. The finding that the biological activity of osteogenin can be restored and delivered by a substratum with defined geometry other than the insoluble collagenous matrix may form the basis of the potential therapeutic application of bone morphogenetic proteins.

Further studies on central actions of nitroglycerin and lack of evidence for nitroglycerin interacting on [3H]clonidine binding sites in cortex membranes

Decerebration and transection of the spinal cord totally abolished the hypotensive and tachycardiac responses to i.c.v injection of nitroglycerin (NTG) and reduced the tachycardia induced by i.v. injection of the drug. The hypotensive responses to i.v. injection of sodium nitroprusside were not altered by decerebration. Microinjection of NTG (0.1-1.0 nmol) into anterior hypothalamic medial preoptic area (AH/POA) produced dose-dependent decreases in mean arterial pressure and heart rate, but minimal responses were induced when the same doses of NTG were injected into the rostral ventrolateral medulla. Pretreatment with rauwolscine (2.5 nmol), injected into the AH/POAs, antagonized the depressor responses to NTG when it was administered into the areas or given i.v. However, rauwolscine did not alter the depressor responses induced by i.v. sodium nitroprusside. Prazosin (1.5 nmol) in the AH/POA did not alter the bradycardic effects induced by microinjection of NTG into the areas. (minus)-Epinephrine significantly interacted with alpha-2 adrenoceptor binding sites, but serotonin and NTG did not interact with [3H] clonidine binding sites in cortex membranes. Results suggest that cardiovascular responses after i.v. injection of NTG involve central and peripheral component. AH/POA is one of the central sites involved in the depressor effects of NTG. NTG-induced modulation of noradrenergic transmission appears to stimulate alpha-2 adrenoceptors in the central nervous system, but the drug does not involve direct interaction with alpha-2 adrenoceptors. Hypotensive effects of sodium nitroprusside result from its action at peripheral sites.

[The effects of nitroglycerin on refractory congestive heart failure by intravenous infusion]

Noninvasive hemodynamic and clinical studies were carried out in 24 patients with congestive heart failure refractory to digitalis, diuretics and vasodilators. Nitroglycerin was given by intravenous infusion for 5-7 days. The results showed that the symptoms, signs and hemodynamic parameters were markedly improved. The overall clinical effective rate was 96% and no serious side effect was noted.

[Pharmacological study on spleen-stomach warming and analgesic actions of Aconitum carmichaeli Debx]

This study presents an observation of the anti-inflammatory effect of Aconitum carmichaeli decoction on water-immersion stress induced gastric ulcer in mice and 0.6 mol/L HCl induced gastric ulcer in rats. The observation showed that the decoction was resistant to the castor oil induced and Cassia angustifolia leaf induced experimental diarrhea in mice, and also had marked analgesic action. It is thus suggested that Aconitum carmichaeli is useful clinically as a spleen-stomach warming and analgesic agent in traditional Chinese medicine.

A new method for clitoroplasty in male-to-female sex reassignment surgery

Sex reassignment surgery has proved to be the best resolution for primary transsexuals. In 1980, Dr. Rubin stated that preservation of the glans to reconstruct the clitoris in male-to-female sex reassignment surgery gave good cosmetic and functional results. In his series, Rubin used the corpus spongiosum as the vascular pedicle of the neoclitoris, but urine leakage is a complication. From 1988 to the present, the dorsal portion of the glans penis with the dorsal neurovascular pedicle has been used here for clitoroplasty in nine male-to-female primary transsexuals. All neoclitorides survived well, with good preservation of light touch and sexual sensation. No urine leakage has occurred. Six patients who were followed reported sexual satisfaction.

Molecular cytogenetic study of short arm aberrations in human D, G group chromosomes

Six cases of Dp+/Gp+, 10 cases of D/G translocation, 1 case of supernumerary marker chromosome, and 1 case of Yqs were studied using molecular and cytogenetic techniques. The Ag-NOR frequencies of the Dp+ and Gp+ groups were found to be higher than those of normal controls, while their satellite association frequencies were lower. Autoradiographic silver grains were not significantly distributed along the p+ part of the marker chromosome as revealed by chromosomal in situ hybridization using an rRNA probe. This result differs from our previous report. It is suggested that there might be different mechanisms for the formation of p+ on acrocentric chromosomes. D/G translocation cases were found to have lost their NOR. A study of supernumerary marker chromosomes and Yqs cases suggested that the marker chromosome and Yqs exerted no phenotypic effect. The mechanism of their formation is discussed.

Xenogeneic osteogenin, a bone morphogenetic protein, and demineralized bone matrices, including human, induce bone differentiation in athymic rats and baboons

Subcutaneous implantation of xenogeneic demineralized bone matrix does not initiate endochondral bone differentiation. Dissociative extraction in 4 M guanidine-HCl or 6 M urea has shown that the apparent species-specificity of intact bone matrix resides in its insoluble immunogenic component, since there is homology in solubilized osteogenic proteins amongst mammals. To further investigate the species-specificity and cross-species reactivity of bone matrix components, baboon and human demineralized bone matrix (DBM) and bovine osteogenin, purified greater than 50,000-fold and with an apparent molecular mass of 28-42 kilodaltons, were implanted in the subcutaneous space of athymic and euthymic rats and into the rectus abdominis of 16 baboons (Papio ursinus). Baboon DBM was also implanted in athymic and euthymic mice. Alkaline phosphatase activity and histology of implants harvested at day 11 and 30 showed that baboon and human DBM induced endochondral bone differentiation both in athymic rats and baboons. Bovine osteogenin in conjunction with baboon insoluble collagenous matrix induced extensive bone differentiation in athymic rats and baboons. Baboon and human DBM did not induce bone differentiation in euthymic rats and, in athymic mice, baboon DBM failed to induce bone differentiation, determining instead the recruitment of multinucleated giant cells. The results indicate that in rodents bone differentiation induced by intact bone matrix is species specific and that T-cell functions are not a requirement for bone induction, although immunologically competent rats block bone differentiation from xenogeneic matrix. Bone differentiation induced by human DBM in baboons suggests that intact bone matrices may not be species-specific amongst primates.(ABSTRACT TRUNCATED AT 250 WORDS)

Histologic comparison of regeneration in human intrabony defects when osteogenin is combined with demineralized freeze-dried bone allograft and with purified bovine collagen

A bone-inductive protein, osteogenin, has been isolated from long bones of humans and offers promise as a grafting material. Studies, however, suggest that osteogenin must be combined with a bone-derived matrix in order to initiate bone differentiation. The purpose of this study was to determine if osteogenin combined with demineralized freeze dried bone allograft (DFDBA), a bone-derived matrix, and with a bovine tendon-derived matrix will enhanced regeneration of intrabony defects in humans. The tendon-derived matrix and DFDBA used alone served as controls. The ability of each material to form a new attachment apparatus was evaluated independently in submerged and nonsubmerged environments in 2 patient populations. Lymphocyte testing was performed to assess development of an immune reaction to osteogenin. The most apical level of calculus on the root served as the histologic reference point to measure regeneration. Biopsies were obtained at 6 months and regeneration was measured histomorphometrically by 2 blinded evaluators. Serial sections from 36 submerged defects in 8 patients and 50 nonsubmerged defects in 6 patients were submitted for statistical analysis. Mean results indicate that osteogenin combined with DFDBA significantly enhanced regeneration of a new attachment apparatus and component tissues in a submerged environment. DFDBA plus osteogenin and DFDBA alone formed significantly more new attachment apparatus and component tissues than either the tendon-derived matrix plus osteogenin or the tendon-derived matrix alone in both submerged and nonsubmerged environments. There were no significant differences between the tendon-derived matrix plus osteogenin and the tendon-derived matrix alone in either the submerged or nonsubmerged environment. Osteogenin does not impair normal lymphocyte blastogenesis at 6 months postsurgical challenge.

[Studies on warming the middle-jiao and analgesic effect of flos Caryophylli]

The effects of water extract and ether extract of Flos Caryophylli have been investigated by four experimental gastric ulcer models, choleresis in rats, two diarrhea models in mice, two pain stimulations in mice, and acute liver injury induced by CCl4 in rats. The results suggest that the action of Flos Caryophylli on dispelling the cold by warming the middle-jiao and curing abdominalgia is related to its anti-ulcer, choleresis increasing, anti-diarrhea and analgesic functions.

Developmental Regulation of the (1,3)-beta-Glucan (Callose) Synthase from Tomato : Possible Role of Endogenous Phospholipases

Activity levels of UDP-glucose: (1,3)-beta-glucan (callose) synthase in microsomal membranes of pericarp tissue from tomato fruit (Lycoperisicon esculentum Mill, cv Rutgers) were determined during development and ripening. Addition of the phospholipase inhibitors O-phosphorylcholine and glycerol-1-phosphate to homogenization buffers was necessary to preserve enzyme activity during homogenization and membrane isolation. Enzyme activity declined 90% from the immature green to the red ripe stage. The polypeptide composition of the membranes did not change significantly during ripening. The enzyme from immature fruit was inactivated by exogenously added phospholipases A(2), C, and D. These results suggest that the decline in callose synthase activity during ontogeny may be a secondary effect of endogenous lipase action.

[Clinical application of Chinese forearm flap: 5-year review]

Twenty-nine patients treated with the Chinese forearm flap from 1985 to 1989 were reviewed. This flap was used for soft tissue defect reconstruction in 19 cases, and phallus reconstruction in 10 patients. There were two cases of total flap failure and two cases of partial failure. Twenty cases used sensory flaps. Donor site complications included partial loss of the skin graft with tendon exposure in one patient (3.4%), limitation of range of movement of the wrist joint in one case (3.4%), and paresthesia over the radial site of the hand in 12 patients. On functional evaluation, 20 patients demonstrated no significant loss of strength in the donor extremity.

Squamous cell carcinoma of the lip

We reviewed 39 cases of squamous cell carcinoma of lip from 53 consecutive patients with carcinoma of the lip. The retrospective review includes age, location, risk factors, TNM classification, histologic differentiation, treatment methods, recurrent disease, site of recurrence, and follow-up status. Results reveal prognosis is related to original tumor size, local recurrence, and presence of cervical metastasis. Aggressive surgical treatment is recommended for identifiable poor prognostic lesions and includes surgical excision, prophylactic suprahyoid neck dissection, and possible radical neck dissection.

Treatment of 910 cases of atrophic gastritis with wei you decoction

In treatment of 910 cases of chronic atrophic gastritis with Wei You Decoction, the overall effective rate was 96.9%. The disease was considered as due to deficiency of vital energy with stagnation of cold, and therefore treatment was to invigorate blood circulation. The Wei You Decoction had functions of replenishing vital energy, warming the middle burner, invigorating blood circulation, and resolving stasis, thus reversing the morbid process in the gastric mucosa. It was nontoxic, and the side-effects were minimal. The therapeutic effect was prompt and persistent. No malignant change was observed after taking the drug.

Use of experimental aneurysms to evaluate wrapping materials

Experimental venous pouch aneurysms in rats were wrapped with muscle, bovine collagen, muslin, cotton, or polyvinyl alcohol. The rats were killed 6 or 12 weeks later, and the aneurysms were compared with control aneurysms. Bovine collagen and muscle were reabsorbed and the aneurysms were similar to the control group. Cotton, muslin, and polyvinyl alcohol caused fibrosis around the aneurysm. However, giant aneurysms were found in the muslin and polyvinyl alcohol group. Cotton appears to be the most suitable material for wrapping aneurysms. The experimental venous pouch aneurysm model in rats can be used to evaluate wrapping materials.

Bifurcation analysis of nonlinear retinal horizontal cell models. II. Network properties

1. We have previously presented a model of horizontal-cell soma isolated from fish retina. The model consists of a synaptic conductance representing input from photoreceptors in parallel with voltage-dependent membrane currents. Membrane-current models are based on I-V curves measured in isolated fish horizontal cells. Bifurcation theory was used to analyze model properties. The major findings of this study were 1) the inward Ca2+ current must be inactivated to account for horizontal-cell resting potentials and hyperpolarizing responses to light stimuli in a background of dark, and 2) the synaptic conductance controls the bifurcation structure of the model, with bistable behavior occurring at small and monostable behavior occurring at larger values of the synaptic conductance. The synaptic conductance at the point of transition from bistable to monostable behavior corresponds to the activation of as few as 100 synaptic channels. Thus tonic synaptic input from photoreceptors and inactivation of the inward Ca2+ current act to "linearize" responses of isolated horizontal-cell models. 2. The model described in this paper extends these analyses to large networks of horizontal cells in which each cell is coupled resistively to its nearest neighbors and is modeled with the use of the full complement of nonlinear membrane currents. Network responses to arbitrary patterns of conductance change (simulating inputs from photoreceptors), current-, or voltage-clamp stimuli are computed using the Newton iteration. The Newton descent direction is computed using either conjugate gradient (CG) or preconditioned CG algorithms. 3. An analysis of network stability properties is performed. Network I-V curves are computed by voltage-clamping the center node and computing the current required to maintain the clamp voltage. Computations are performed on networks of model cells in which the Ca2+ current is fully activated and the synaptic conductance is zero, thus making each cell as nonlinear as possible. Coupling conductance values slightly greater than 100 pS provide a current shunt sufficient to prevent the generation of Ca2+ action potentials in the network. This coupling conductance corresponds to the conductance of as few as two gap-junction channels and is more than two orders of magnitude less than the coupling known to exist between pairs of cultured horizontal cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Ambient temperature modulation of fenfluramine-induced thermogenesis in the rat

The anti-obesity drug fenfluramine, promotes loss of weight by reducing food intake; however, there is controversy as to whether the drug can also elevate expenditure of energy. Resting consumption of oxygen (VO2) was measured in conscious rats to determine whether the injection of fenfluramine increased metabolic rate and whether prior fasting, or ambient temperature altered the response. Regardless of whether the rats were fed or had been fasted for 22 hr, in a thermoneutral environment (28 degrees C), the intraperitoneal injection of dl-fenfluramine (20 mg/kg) caused a raised oxygen consumption. This elevation was sustained to the end of the 60-min period of measurement after the injection, at which point the colonic temperature was found to be increased. This metabolic response to fenfluramine was largely attenuated when the drug was administered at 23 degrees C, and the colonic temperature of the rats was decreased by 60 min after the injection. At 4 degrees C, the injection of fenfluramine inhibited thermogenesis against cold, the oxygen consumption fell and the rats exhibited hypothermia. It was concluded that fenfluramine can increase the metabolic rate, but that this effect is not conditional on associated food intake, as has been reported. Rather, the ambient temperature governs whether stimulation or inhibition of thermogenesis will be evoked. These metabolic effects of fenfluramine explain, in part, its divergent effects on body temperature, reported previously.

The chromosomal complements of cleaved human embryos resulting from in vitro fertilization

Chromosome preparations were made from 25 cleaved abnormal human embryos at the two- to eight-cell stage after in vitro fertilization. Morphologically, these embryos showed either variable degrees of degeneration or an abnormal number of pronuclei before first cleavage. Among 14 successfully karyotyped embryos, only 3 had a normal chromosomal complement. Eleven showed chromosomal abnormalities, including triploidy, haploidy, and mosaicism. This finding documents a high incidence of chromosomal errors in morphologically abnormal early preimplantation embryos.

Mid-term effects of neodymium: YAG transscleral cyclocoagulation in glaucoma

Neodymium: YAG (Nd:YAG) transscleral cyclocoagulation successfully lowers intraocular pressure (IOP) over the short term in animals and humans. Twenty-eight eyes with uncontrolled glaucoma were prospectively followed over a mean period of 21.9 months. Mean pretreatment IOP was 47.5 mmHg. Mean posttreatment IOP was 19.9 mmHg (P less than 0.005). Mean (+/- standard deviation) number of treatments was 1.86 (+/- 1.11) Mean number of drugs used before and after treatment was 3.28 and 2.48, respectively (P less than 0.01). A total of 10.7% eyes went phthisical. Thirty percent of eyes with vision and good IOP control (i.e., less than 21 mmHg) lost some vision after the procedure. Neodymium:YAG transscleral cyclocoagulation appears to be an effective method of controlling IOP over the mid-term, but is associated with significant complications.

Reconstruction of anorectal angle after abdominoperineal resection of rectum and anus--an animal model

Voluntary control of the bowel movements is a social necessity. Lack of control relegates one to psychological debility and the possible need for a permanent colostomy. Anorectal angle plays an important role in fecal continence. In the normal individual, this angle lies in the range of 60 to 105 degrees. Perineal colostomy, once proposed for patients who had received abdominoperineal resection (APR), has been abandoned because of frank incontinence. This study used a canine model. The anorectal angle, external sphincter, internal sphincter, and the puborectalis were all destroyed after APR. The colon was pulled through the perineal defect. Enteropexy, gracilis muscle transfer, and perineal colostomy were performed to restore the anorectal angle. Barium enema was performed preoperatively and postoperatively. The anorectal angle was reconstructed within normal ranges after abdominoperineal resection of the rectum and anus.

Purification and partial amino acid sequence of osteogenin, a protein initiating bone differentiation

Osteogenin was purified from bovine bone matrix and its activity monitored by an in vivo bone induction assay. The purification method utilized extraction of the bone-inducing activity with 6 M urea, followed by chromatography on heparin-Sepharose, hydroxyapatite, and Sephacryl S-200. Active fractions were further purified by preparative sodium dodecyl sulfate gel electrophoresis without reduction. Osteogenin activity was localized in a zone between 30 and 40 kDa. The amino acid sequences of a number of tryptic peptides of the gel-eluted material were determined. Reduction and alkylation of purified osteogenin in 7 M guanidine hydrochloride resulted in the total loss of biological activity. Sodium dodecyl sulfate gel electrophoresis under reducing conditions revealed a broad band with an apparent molecular mass of 22 kDa.