Lower Affinity of Isradipine for L-Type Ca2+ Channels during Substantia Nigra Dopamine Neuron-Like Activity: Implications for Neuroprotection in Parkinson's Disease

Ca2+-influx through L-type Ca2+-channels (LTCCs) is associated with activity-related stressful oscillations of Ca2+ levels within dopaminergic (DA) neurons in the substantia nigra (SN), which may contribute to their selective degeneration in Parkinson's disease (PD). LTCC blockers were neuroprotective in mouse neurotoxin models of PD, and isradipine is currently undergoing testing in a phase III clinical trial in early PD. We report no evidence for neuroprotection by in vivo pretreatment with therapeutically relevant isradipine plasma levels, or Cav1.3 LTCC deficiency in 6-OHDA-treated male mice. To explain this finding, we investigated the pharmacological properties of human LTCCs during SN DA-like and arterial smooth muscle (aSM)-like activity patterns using whole-cell patch-clamp recordings in HEK293 cells (Cav1.2 α1-subunit, long and short Cav1.3 α1-subunit splice variants; β3/α2δ1). During SN DA-like pacemaking, only Cav1.3 variants conducted Ca2+ current (ICa) at subthreshold potentials between action potentials. SN DA-like burst activity increased integrated ICa during (Cav1.2 plus Cav1.3) and after (Cav1.3) the burst. Isradipine inhibition was splice variant and isoform dependent, with a 5- to 11-fold lower sensitivity to Cav1.3 variants during SN DA-like pacemaking compared with Cav1.2 during aSM-like activity. Supratherapeutic isradipine concentrations reduced the pacemaker precision of adult mouse SN DA neurons but did not affect their somatic Ca2+ oscillations. Our data predict that Cav1.2 and Cav1.3 splice variants contribute differentially to Ca2+ load in SN DA neurons, with prominent Cav1.3-mediated ICa between action potentials and after bursts. The failure of therapeutically relevant isradipine levels to protect SN DA neurons can be explained by weaker state-dependent inhibition of SN DA LTCCs compared with aSM Cav1.2.SIGNIFICANCE STATEMENT The high vulnerability of dopamine (DA) neurons in the substantia nigra (SN) to neurodegenerative stressors causes Parkinson's disease (PD). Ca2+ influx through voltage-gated L-type Ca2+ channels (LTCCs), in particular Cav1.3, appears to contribute to this vulnerability, and the LTCC inhibitor isradipine is currently being tested as a neuroprotective agent for PD in a phase III clinical trial. However, in our study isradipine plasma concentrations approved for therapy were not neuroprotective in a PD mouse model. We provide an explanation for this observation by demonstrating that during SN DA-like neuronal activity LTCCs are less sensitive to isradipine than Cav1.2 LTCCs in resistance blood vessels (mediating dose-limiting vasodilating effects) and even at supratherapeutic concentrations isradipine fails to reduce somatic Ca2+ oscillations of SN DA neurons.

L-type Ca2+ channels in heart and brain

L-type calcium channels (Cav1) represent one of the three major classes (Cav1–3) of voltage-gated calcium channels. They were identified as the target of clinically used calcium channel blockers (CCBs; so-called calcium antagonists) and were the first class accessible to biochemical characterization. Four of the 10 known α1 subunits (Cav1.1–Cav1.4) form the pore of L-type calcium channels (LTCCs) and contain the high-affinity drug-binding sites for dihydropyridines and other chemical classes of organic CCBs. In essentially all electrically excitable cells one or more of these LTCC isoforms is expressed, and therefore it is not surprising that many body functions including muscle, brain, endocrine, and sensory function depend on proper LTCC activity. Gene knockouts and inherited human diseases have allowed detailed insight into the physiological and pathophysiological role of these channels. Genome-wide association studies and analysis of human genomes are currently providing even more hints that even small changes of channel expression or activity may be associated with disease, such as psychiatric disease or cardiac arrhythmias. Therefore, it is important to understand the structure–function relationship of LTCC isoforms, their differential contribution to physiological function, as well as their fine-tuning by modulatory cellular processes.

A direct comparison of the pharmacodynamic properties of insulin detemir and neutral protamine lispro insulin in patients with type 1 diabetes

AIMS

To compare the pharmacodynamic properties of insulin detemir (detemir) and neutral protamine lispro (NPL) insulin using a euglycaemic glucose clamp.

METHODS

In a double-blind, crossover study, 30 patients with C-peptide negative type 1 diabetes were randomly assigned to a single dose (0.4 U/kg) of detemir and NPL. Plasma glucose (PG) was normalized with a variable insulin infusion and then decreased stepwise, followed by a euglycaemic clamp at 5.5 mmol/l over 32 h. Duration of action was defined as time from dosing until PG exceeded 8.3 mmol/l for at least 30 min.

RESULTS

Duration of action was similar for detemir [23.0 (range 2.25-32) h] and NPL [22.0 (9.5-32) h], p = 0.55. Using glucose infusion rate (GIR) parameters, detemir showed a flatter pharmacodynamic profile versus NPL: area under the curve, AUC(GIR) ((0-32))  = 1326 vs. 1841 mg/kg, p < 0.01 (detemir vs. NPL, respectively); AUC(GIR) ((0-12))  = 784 vs. 1392 mg/kg, p < 0.05; AUC(GIR) ((12-32))  = 455 vs. 274 mg/kg, p = 0.051; GIR(late) (12-32)/GIR(early) (0-12) ratio = 0.33 vs. 0.04, p < 0.001. Detemir also showed a lower and later peak of action than NPL [GIR(max) 2.0 vs. 3.2 mg/kg/min, p < 0.01; T(max) 9.1 (95% confidence interval: 3.0-14.7) vs. 7.0 h (1.8-15.2)].

CONCLUSIONS

Detemir and NPL had similar duration of action of approximately 24 h in patients with type 1 diabetes. Compared with NPL, detemir had a flatter profile with a more even distribution of metabolic effect over 24 h.

Vitamin D: role in autoimmunity

Abstract

Vitamin D has long been known for its important effects on bone health and calcium/phosphate homoeostasis, but vitamin D deficiency is now being linked to a broadening field of health problems, including autoimmune diseases. Over the last 5 years, our perspective on how vitamin D interacts with the immune system has dramatically changed. Prominent new data have shown that the expression and activity of vitamin D metabolizing enzymes are central to normal immune responses, providing a mechanism for the localized metabolism from inactive vitamin D - 25(OH)D - to active vitamin D - 1,25(OH)₂D - at the site of inflammation. Vitamin D influences the function of cells intrinsic to innate and adaptive immunity, and has an important role in the regulation of inflammatory response as well as maintaining immune homoeostasis. Inadequate vitamin levels, which probably are different from those necessary to maintain bone homoeostasis, are linked to higher susceptibility of autoimmune diseases such as type 1 diabetes (T1D), inflammatory bowel disease (IBD) or multiple sclerosis (MS). Vitamin D supplementation trials will further elucidate the in vivo effects of vitamin D on the immune system and its ability to influence autoimmune diseases.

Functional properties of a newly identified C-terminal splice variant of Cav1.3 L-type Ca2+ channels

An intramolecular interaction between a distal (DCRD) and a proximal regulatory domain (PCRD) within the C terminus of long Ca(v)1.3 L-type Ca(2+) channels (Ca(v)1.3(L)) is a major determinant of their voltage- and Ca(2+)-dependent gating kinetics. Removal of these regulatory domains by alternative splicing generates Ca(v)1.3(42A) channels that activate at a more negative voltage range and exhibit more pronounced Ca(2+)-dependent inactivation. Here we describe the discovery of a novel short splice variant (Ca(v)1.3(43S)) that is expressed at high levels in the brain but not in the heart. It lacks the DCRD but, in contrast to Ca(v)1.3(42A), still contains PCRD. When expressed together with α2δ1 and β3 subunits in tsA-201 cells, Ca(v)1.3(43S) also activated at more negative voltages like Ca(v)1.3(42A) but Ca(2+)-dependent inactivation was less pronounced. Single channel recordings revealed much higher channel open probabilities for both short splice variants as compared with Ca(v)1.3(L). The presence of the proximal C terminus in Ca(v)1.3(43S) channels preserved their modulation by distal C terminus-containing Ca(v)1.3- and Ca(v)1.2-derived C-terminal peptides. Removal of the C-terminal modulation by alternative splicing also induced a faster decay of Ca(2+) influx during electrical activities mimicking trains of neuronal action potentials. Our findings extend the spectrum of functionally diverse Ca(v)1.3 L-type channels produced by tissue-specific alternative splicing. This diversity may help to fine tune Ca(2+) channel signaling and, in the case of short variants lacking a functional C-terminal modulation, prevent excessive Ca(2+) accumulation during burst firing in neurons. This may be especially important in neurons that are affected by Ca(2+)-induced neurodegenerative processes.

Assessment of different techniques for subcutaneous glucose monitoring in Type 1 diabetic patients during 'real-life' glucose excursions

AIMS

To compare the accuracy of two marketed subcutaneous glucose monitoring devices (Guardian RT, GRT; GlucoDay S, GDS) and standard microdialysis (CMA60; MD) in Type 1 diabetic patients.

METHODS

Seven male Type diabetic patients were investigated over a period of 26 h simulating real-life meal glucose excursions. Catheters of the three systems were inserted into subcutaneous adipose tissue of the abdominal region. For MD, interstitial fluid was sampled at 30- to 60-min intervals for offline glucose determination. Reference samples were taken at 15- to 60-min intervals. All three systems were prospectively calibrated to reference. Median differences, median absolute relative differences (MARD), median absolute differences (MAD), Bland-Altman plot and Clark Error Grid were used to determine accuracy.

RESULTS

Bland-Altman analysis indicated a mean glucose difference (2 standard deviations) between reference and interstitial glucose of -10.5 (41.8) % for GRT, 20.2 (55.9) % for GDS and 6.5 (35.2) % for MD, respectively. Overall MAD (interquartile range) was 1.07 (0.39; 2.04) mmol/l for GRT, 1.59 (0.54; 3.08) mmol/l for GDS and 0.76 (0.26; 1.58) mmol/l for MD. Overall MARD was 15.0 (5.6; 23.4) % (GRT), 19.7 (6.1; 37.6) % (GDS) and 8.7 (4.1; 18.3) % (MD), respectively. Total sensor failure occurred in two subjects using GRT and one subject using GDS.

CONCLUSIONS

The three investigated technologies had comparable performance. Whereas GRT underestimated actual blood glucose, GDS and MD overestimated blood glucose. Considerable deviations during daily life meal glucose excursions from reference glucose were observed for all three investigated technologies. Present technologies may require further improvement until individual data can lead to direct and automated generation of therapeutic advice in diabetes management.

Insulin glulisine, insulin lispro and regular human insulin show comparable end-organ metabolic effects: an exploratory study

AIMS

To compare the end-organ metabolic effects of insulin glulisine (glulisine), insulin lispro (lispro) and regular human insulin (RHI) in patients with type 1 diabetes mellitus.

METHODS

Eighteen patients with type 1 diabetes mellitus (mean age 36.9 +/- 8.6 years, BMI 23.6 +/- 2.8 kg/m(2), haemoglobin A(1c) 7.4 +/- 0.9%) were randomized in this single-centre, double-blind, three-period cross-over, standard Latin-square, euglycaemic glucose clamp trial. Patients received sequential, primed stepwise intravenous infusions of glulisine, lispro or RHI (infusion rates were increased in a stepwise manner from an initial rate of 0.33 [180 min] to 0.66 [180 min] and 1.00 [180 min] mU/kg/min). The primary variables were the suppression of endogenous glucose production (S(EGP)) and glucose uptake (GU).

RESULTS

Mean basal endogenous glucose production (EGP) was 1.88, 2.12 and 2.12 mg/kg/min for glulisine, lispro and RHI respectively. Mean (+/-s.e.) maximum absolute S(EGP) (adjusted for basal EGP) was -1.64 +/- 0.06, -1.72 +/- 0.05 and -1.56 +/- 0.05 mg/kg/min respectively. Mean (+/-s.e.) maximum absolute increase in GU (adjusted for basal GU) was 6.46 +/- 0.26, 6.23 +/- 0.24 and 6.72 +/- 0.24 mg/kg/min respectively. There were no clinically relevant differences between the three insulin treatments with respect to serum insulin, free fatty acid (FFA), glycerol or lactate levels. No serious adverse events and no episodes of severe hypoglycaemia were reported.

CONCLUSIONS

This study shows that glulisine, lispro and RHI have similar effects on S(EGP), GU, FFA, glycerol and lactate levels, providing evidence for similar end-organ metabolic effects.

Long-term evaluation of a structured outpatient education programme for intensified insulin therapy in patients with Type 1 diabetes: a 12-year follow-up

AIMS/HYPOTHESIS

This study was conducted to evaluate the long-term outcome of a structured outpatient diabetes teaching and treatment programme (DTTP) for intensified insulin therapy in patients with Type 1 diabetes, which aims to improve metabolic control without increasing the risk of severe hypoglycaemia.

METHODS

All 123 diabetic outpatients (age 41+/-14 years; 64 women; BMI 23.5+/-3.1; diabetes duration 17+/-11 years; HbA1c 7.9+/-1.6%; 32 patients with a history of severe hypoglycaemia; 18 with overt nephropathy; 22 with proliferative retinopathy) who participated in the DTTP between June 1989 and June 1990 were invited for follow-up visits after 3, 6 and 12 years.

RESULTS

Out of the 123 patients, 11 died during the follow-up period, two were lost for follow-up, and one was not willing to participate in re-evaluation after 12 years. Mean HbA1c levels decreased from 7.9+/-1.6% to 7.1+/-1.2% (p<0.01) after 3 years, and were 7.8+/-1.5% (NS) and 7.8+/-1.2% (NS) after 6 and 12 years respectively. Frequency of hypoglycaemia decreased from 0.49 episodes per patient per year to 0.14 after 3 years (p<0.01), 0.19 after 6 years (p<0.01) and 0.16 after 12 years (p<0.01). Of the participants, 41% were able to lower HbA1c levels without episodes of severe hypoglycaemia and to maintain this improvement at all follow-up visits over the 12-year period. At follow-up, intensified insulin therapy was carried out by 94% of the patients.

CONCLUSIONS/INTERPRETATION

A sustained reduction of the incidence of severe hypoglycaemia was observed in patients with Type 1 diabetes after participation in a structured outpatient DTTP over a 12-year period.

Subduction and collision processes in the Central Andes constrained by converted seismic phases

The Central Andes are the Earth's highest mountain belt formed by ocean-continent collision. Most of this uplift is thought to have occurred in the past 20 Myr, owing mainly to thickening of the continental crust, dominated by tectonic shortening. Here we use P-to-S (compressional-to-shear) converted teleseismic waves observed on several temporary networks in the Central Andes to image the deep structure associated with these tectonic processes. We find that the Moho (the Mohorovicić discontinuity--generally thought to separate crust from mantle) ranges from a depth of 75 km under the Altiplano plateau to 50 km beneath the 4-km-high Puna plateau. This relatively thin crust below such a high-elevation region indicates that thinning of the lithospheric mantle may have contributed to the uplift of the Puna plateau. We have also imaged the subducted crust of the Nazca oceanic plate down to 120 km depth, where it becomes invisible to converted teleseismic waves, probably owing to completion of the gabbro-eclogite transformation; this is direct evidence for the presence of kinetically delayed metamorphic reactions in subducting plates. Most of the intermediate-depth seismicity in the subducting plate stops at 120 km depth as well, suggesting a relation with this transformation. We see an intracrustal low-velocity zone, 10-20 km thick, below the entire Altiplano and Puna plateaux, which we interpret as a zone of continuing metamorphism and partial melting that decouples upper-crustal imbrication from lower-crustal thickening.

[Laparoscopic cholecystectomy]

The appropriateness of a laparoscopic approach to cholecystectomy in community hospital settings has been questioned. To address this issue a prospective study of outcomes of laparoscopic cholecystectomies performed during a three year period at Telemark Community Hospital was undertaken. There were 229 procedures performed by five surgeons. 24 (10.5%) of the attempted laparoscopic cholecystectomies were converted to open cholecystectomies. The average hospital stay after laparoscopic cholecystectomy was 3.0 days (SD = 2.6). Minor intraoperative complications (gall bladder perforation, gall bladder bed bleeding) occurred in 43% of the laparoscopic procedures. There were nine cases (4.4%) of major intraoperative complications which included laceration of the common bile duct (n = 4, one discovered during surgery), ileal perforation (n = 1) and laceration of the liver (n = 4). The frequency of postoperative complications after laparoscopic cholecystectomy was 8.8%. Bile peritonitis was observed in three patients, of whom one died. There were no significant differences in intra- and postoperative complications between the surgeons performing the operations. The present results support the argument that laparoscopic cholecystectomies can be performed safely and effectively in community hospitals.

Neopterin and 7,8-dihydroneopterin induce apoptosis in the rat alveolar epithelial cell line L2

The neopterin derivatives, neopterin and 7,8-dihydroneopterin, modulate the cellular oxidant-antioxidant balance as well as the expression of the inducible nitric oxide synthase (iNOS) gene. Since apoptosis can be induced by reactive oxygen intermediates and nitric oxide (NO) we investigated whether these neopterin derivatives induce apoptotic cell death. As model we selected the rat alveolar epithelial cell line L2. 24 h incubation of neopterin (1-1000 microM) as well as 7,8-dihydroneopterin (1-1000 microM) resulted in a significant increase of percent apoptotic cells (measured by FACS analysis). Coincubation of both pteridines with the cytomix (interferon-gamma plus tumor necrosis factor-alpha) led to a significantly higher apoptosis than the cytomix alone. In contrast to the cytomix, no iNOS gene expression and no NO release could be detected after incubation with neopterin or 7,8-dihydroneopterin. We conclude that neopterin and 7,8-dihydroneopterin are per se inducers of apoptosis which is not mediated by nitric oxide. This may be of importance in inflammatory pulmonary diseases associated with an activation of the cellular immune system.

Comparative effects of heme and metalloporphyrins on interferon-gamma-mediated pathways in monocytic cells (THP-1)

Previous results have demonstrated links between cell-mediated immunity, interferon (IFN)-gamma and neopterin production with heme, porphyrins, and iron metabolism. In this study, we compared the effects of heme, several metalloporphyrins, protoporphyrin IX, and iron on the signal or IFN-gamma-mediated pathways, such as the expression of major histocompatibility complex class II antigens, neopterin formation, and the degradation of tryptophan. Using the human monocytic cell line, THP-1, we found that heme, Zn-mesoporphyrin, Zn-deuteroporphyrin, Co-protoporphyrin, and iron reduced the efficiency of the IFN-gamma signal. In addition, Zn-mesoporphyrin almost fully inhibited IFN-gamma-induced degradation of tryptophan by the heme protein, indoleamine 2,3-dioxygenase. In contrast, tin-protoporphyrin enhanced the IFN-gamma effects as seen by increased neopterin production, enhanced tryptophan degradation, and elevated HLA-DR antigen expression on cells. These effects are considered to be due to the action of heme, metalloporphyrins, iron, or heme byproducts on the IFN-gamma signal, rather than to direct effects on IFN-gamma-induced enzymatic pathways. Heme and metalloporphyrins were previously shown to affect heme oxygenase activity, T cell growth, and lipid peroxidation and to modulate interleukin 2 activity. These pathways are also known to be influenced by IFN-gamma, and our data suggest that heme and metalloporphyrins may directly modulate the efficiency of the IFN-gamma signal.

Postoperative radioactive iodine evaluation of total thyroidectomy for thyroid carcinoma: reappraisal and therapeutic implications

The records of 430 patients who underwent total thyroidectomy with radioactive iodine (RAI) uptake studies performed postoperatively were reviewed. Indications for the administration of an ablative dose of iodine 131 are given. The majority (85.4%) had no or low (less than 2%) evidence of focal uptake and therefore were not treated with ablative doses of iodine 131. RAI scanning is necessary postoperatively to determine the completeness of the surgical procedure and to detect residual or metastatic disease. Small foci of residual disease or occult distant metastases can be adequately treated with therapeutic doses of RAI. Nodal or distant metastases that become clinically evident following thyroidectomy are usually not successfully treated with RAI.

Multicentre evaluation of the temporal bones obtained from a patient with suspected Menière's disease

A multicentre study of the inner ears of an 88-year-old patient with vertiginous spells and severe hearing loss in the left ear was performed, employing regular and block surface preparations, light and electron microscopy with qualitative and quantitative evaluation of the cochlear and vestibular nerves. There was severe hydrops of the left cochlea and saccule. Reissner's membrane extended into the vestibule and herniated into the perilymphatic space of the non-ampullated end of the horizontal canal. Furthermore, the short canal connecting the posterior ampulla with the utricle had a small, exceedingly thin balloon-like expansion. Only slight hydrops limited to the cochlea was found in the right ear. Sensorineural degeneration was much more pronounced in the left cochlea than in the right. The number of cochlear and vestibular nerve fibres was greatly reduced in the left ear where more fibres with degenerative changes were present. In both specimens the number of myelinated nerve fibres in osseous spiral lamina was smaller than that in the cochlear nerve in the internal auditory canal. Changes occurred in the endolymphatic sacs but were considered non-specific. In this case severe, apparently progressive hydrops and sensorineural degeneration, characteristic of Menière's disease, were associated with atypical onset of clinical symptoms at a late age.

Multiple parathyroid adenomas: report of thirty-three cases

An increasing number of patients with primary hyperparathyroidism are found to have two or three enlarged parathyroid glands. Of 865 patients successfully operated on by one surgeon (J.N.A.), multiple enlarged parathyroid glands (adenomas) were found and resected in 33 cases (3.8%), with resulting normocalcemia lasting from 1 to 22 years (mean 5.8). Twenty-nine patients had two adenomas and four had three adenomas. In 28 patients the multiple adenomas were synchronous. Twenty-five patients underwent removal of all of the enlarged parathyroid glands in one operation; in three patients one adenoma was removed, reoperation for persistent hypercalcemia was performed, and a second adenoma was resected with cure. In five patients one adenoma was removed, normocalcemia ensued for 3 to 18 years, and a second (metachronous) adenoma occurred and was resected successfully. Although 10 of 70 enlarged parathyroid glands removed were labeled hyperplasia, cure in all but one of our patients by selective resection of only enlarged parathyroid glands emphasizes the unreliability of histologic criteria in differentiating between parathyroid adenoma and hyperplasia. Based on this study, we support the existence of multiple adenomas and advocate removal of only macroscopically enlarged parathyroid glands in patients with primary hyperparathyroidism.

Breast cancer in the young

Breast cancer in the young is rare. Some cases can be treated with modest surgical intervention and prognosis is good. We present a report of a 17-year-old black girl with adenocarcinoma of the breast. In our case, the disease pursued a devastatingly rapid course in spite of treatment and the patient died within 6 months of diagnosis. The literature relating to clinical experience with various types of breast carcinoma seen in pre- and postpubertal patients is also reviewed. We conclude that this case, and certain other cases cited, demonstrates the need for a high index of suspicion and earlier and more aggressive intervention in young patients with axillary breast masses.

Hair cell distributions in the normal human cochlea. A report of a European working group

Cochlear hair cell counts from individuals who had clinically normal hearing prior to their death have been plotted for various age bands as a function of the number of hair cells per millimetre against their position in the cochlea. Position has been expressed as the distance of that observation of hair cell density from the base of the cochlea, divided by the total length of the cochlea, thereby giving a proportional representation of the cochlea in the range of 0.0 to 1.0 with 20 subdivisions of 0.05. There is an age-related decrease in the number of hair cells in the normal population, and this is more marked for the outer hair cells.

Plasma levels of cyclic nucleotides are elevated in atopic eczema

Plasma cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) taken at distinct times of the day were measured in 45 inpatients with generalized atopic eczema (AE). The results were compared with 34 healthy controls. Female patients not taking oral contraceptives (OC) and male patients revealed significantly higher median levels of cAMP in comparison with the controls (p less than 0.002 for males; p less than 0.001 for females). No significant cAMP differences were found between patients of either sex and female controls taking OC. The median cGMP plasma levels did not differ between patients and controls. Both cyclic nucleotides are discussed under the aspect of cAMP as a second messenger of various hormones, reflecting and integrating different responses of the body to AE as a distressing systemic skin disorder.

A self-sealing dialysis prosthesis. Coaxial double PTFE-silicone graft

The performance of a new dialysis prosthesis designed to self-seal after puncture was tested ex vivo and in vivo. It consists of two coaxial polytetrafluoroethylene tubes (PTFE), the space between them filled with silicone rubber sealant (PTFE-sil). Ex vivo: Three PTFE-sil, three double PTFE (without silicone), and three single PTFE grafts were placed sequentially between scribner shunts in the hind limb of four dogs. Bleeding on puncturing with an 18-gauge needle was measured for 30 seconds. PTFE-sil bled less than the controls (g): PTFE-sil; 16 +/- 18; double PTFE: 32 +/- 10; single PTFE: 52 +/- 19 (p less than 0.001). In vivo: Six PTFE-sil and five single PTFE grafts were interposed between the carotid artery and jugular vein of dogs and were punctured with a 16-gauge needle on days 1, 3, and 7. Bleeding was measured through an incision over the puncture site at 5 minutes. In 11 punctures of PTFE-sil, there was no bleeding; three bled less than 20 g. In 13 control punctures, none bled less than 70 g. Patency: Grafts were studied for patency in arteriovenous (AV) fistulas in 34 dogs. Each dog received a PTFE-sil graft in one groin and a single PTFE control graft in the other. At 4 months, patency rates were: PTFE-sil, 84%; single PTFE, 87% (NS). Four months after implantation, hemostasis after puncture in PTFE-sil grafts required 70 +/- 49 seconds versus 207 +/- 48 seconds for PTFE grafts (p less than 0.005). In conclusion, PTFE-sil grafts are self-sealing, can be used immediately after implantation, and need minimal compression after needle removal.

Pancreas preservation with TP-IV: a hyperosmolar colloid solution

This study compares the efficacy of a new hyperosmolar colloid solution (TP-IV) with Euro-Collins solution for long-term (72 hr) hypothermic storage of canine pancreas autografts. Four experimental recipient groups and their survival (30-day study period) results were as follows: Gr. I (n = 6) pancreatectomized controls, without autotransplant (X +/- SD = 5.83 +/- 3.06 days); Gr. II (n = 6) fresh nonpreserved autografts (X +/- SD = 23.83 +/- 10.12 days, 5 of 6 greater than 30 days); and Gr. III (n = 7) and Gr. IV (n = 5) receiving pancreas autografts stored at 4 degrees C for 72 hr in either Euro-Collins or TP-IV, respectively (Gr. III, 13.85 +/- 9.04 days; Gr. IV, 21.2 +/- 12.37 days). The results appear to indicate that TP-IV is superior to Euro-Collins solution for 72-hr hypothermic storage of pancreas grafts. In fact, survival in the TP-IV-presented group was comparable to that of fresh, non-preserved autografts.

[Complications following duodenopancreatectomy in chronic pancreatitis]

42 partial and 5 total duodenopancreatectomies performed during the last ten years are reported. Complications--fistula, abscess, bleeding, insufficiency--occurred in 21 cases (46.5%). In 11 patients reoperation becomes necessary (23.4%) 6 patients died (12.7%). The advantages of primary partial duodenopancreatectomy comparing to other surgical procedures are discussed. Some surgical techniques in reducing the complication rate are recommended.

Functional histopathology of the human audio-vestibular organ. Euro-Data-Hearing

The present paper describes the setting-up of a new project, sponsored by the Commission of the European Communities, to promote the study of functional histopathology of the human audio-vestibular organ. The project has the purpose of co-ordinating in Europe morphological research on the hearing and equilibrium organ and promoting the comparison of data from clinical, physiological and morphological studies in the field of hearing and equilibrium impairment. A manual (Iurato et al., 1982) has been prepared with the objectives of (1) stimulating clinicians to participate in the project, (2) encouraging the collection of audiological data for comparison with pathology, and (3) supplying clinicians with the necessary information about the technique of fixation and preparation of the specimens. The fixation procedures for the two major techniques of studying ear pathology: (1) microdissection and electron microscopy, and (2) embedding of the whole block for serial sectioning and light microscopy, are described in detail. Special paragraphs deal with the technique of fixation of the brain and with the technique of removal of the temporal bones and brain at autopsy. The instructions for delivery of the specimens and the publication rules are enclosed in the main body of the manual. Appendix 1 contains a list of the participating laboratories. Appendix 2 deals with autopsy legislation in the different European countries. Appendix 3 contains the sender's data sheet which supplies the instructions for collecting the clinical history of the patient and the audiological and vestibular data.

Skeletal muscle regeneration in myopathic hamsters of strain BIO 8262

Skeletal muscle regeneration was studied in polymyopathic hamsters of the strain BIO 8262 by autoradiography. Flash labeling with 3H-thymidine revealed high labeling indices of mononuclear cells in areas with muscle cell necroses and low labeling of "interstitial cells". However, no labeled nuclei were present in myotubes. Three days after multiple injections of the radioisotope, labeled nuclei in the myotubes were present. The mean labeling intensity of these nuclei was slightly elevated on the 15th day. On the third day after multiple 3H-thymidine injections nearly all mononuclear cells were labeled; but their labeling indices slightly decreased until the 15th day. From the decrease of labeling intensity, a high turnover rate of these cells may be assumed. Labeled myotubes appeared in the neighborhood of mononuclear cells as well as in areas without pronounced round cell infiltrations. From labeled myotubes in areas with round cell infiltrations it may be concluded that they arose by fusion of rapidly proliferating satellite cells, which may be constituents of the mononuclear cell population. Labeled myotubes that appeared outside areas of mononuclear cell infiltrations may have been caused by fusion of slow proliferating satellite cells. Despite the fact of a high regeneration capacity of muscle in hamsters of the strain BIO 8262, this process is not sufficient to completely restore the muscle necroses.