Management of chylous ascites following laparoscopic presacral neurectomy

Chylous ascites is an extremely rare complication of laparoscopic presacral neurectomy (LPSN), and treatment is still controversial. Four patients undergoing LPSN for dysmenorrhoea or chronic pelvic pain were complicated with chylous ascites. Two were successfully treated with bipolar cauterization and one, after the failure of initial treatment by bipolar cauterization, was then effectively managed by compression with Gelform and closure of the peritoneum of the presacral area by suture through laparoscopy. The fourth patient had persistent chyle leakage from the drainage tube after electrocauterization and was finally cured by conservative management including removal of the drainage tube and a low-fat diet for 3 weeks. Chylous ascites has not been reported in laparoscopic presacral neurectomy. Management that is quick, effective and subjects the patients to the least amount of suffering is still unresolved. Repeated laparoscopy can be considered to identify the possibility of injury to lymphatic vessels, to relieve abdominal distention due to chyle accumulation, and to apply electrocauterization or compression with Gelform and closure of the peritoneum. Conservative treatment with a low-fat diet may need a longer time. The use of a drainage tube may provide negative pressure allowing a continuous leakage of chyle. However, more controlled study is required to identify the most proper and effective management.      

Management of Nucleus and IOL Drop

Background

Thirty six cases of lenticular nucleus drop following phacoemulsification and 43 cases of posterior dislocation of intraocular lens (IOL) inclusive of two paediatric cases were managed by a modified vitrectomy procedure without using perfluorocarbon liquid (PFCL).

Methods

In these cases the incision was placed inferotemporally at pars plana. The limbal sites of the earlier cataract surgery were utilised as the other two ports. In either case adequate vitrectomy was performed first. In cases of nuclear drop, the nucleus was impaled (speared) with a micro vitreo retinal blade and brought into the anterior chamber from where it was delivered out. In cases of IOL drop the same was picked up by an intra-vitreal forceps.

Result

Of the 77 adult cases treated 57 (74%) of the eyes had a visual recovery of 6/18 or more.

Conclusion

Prompt surgical management in cases of nuclear drop or posterior dislocation of IOL yields good results.Key Words: Phaco-emulsification, Intraocular lens drop, Nucleus drop, Vitrectomy     

Evidence that calpains and elastase do not produce the von Willebrand factor fragments present in normal plasma and IIA von Willebrand disease

Recent evidence suggests that proteolysis plays an important role in some forms of inherited and acquired von Willebrand disease (vWD). Because calpains and one or more enzymes released from polymorphonuclear leukocytes are known to proteolyze von Willebrand factor (vWF) in vitro with resultant loss of large multimers similar to that seen in IIA vWD, they have been suggested as being responsible for the proteolysis in vivo. Using monoclonal epitope mapping, we have examined the proteolysis of the vWF subunit by porcine calcium- activated neutral proteases (calpains) and human leukocyte elastase to determine whether they produce the vWF proteolytic cleavage products seen in normal individuals and IIA vWD. Purified vWF was digested with porcine calpains I and II. We found no difference in the size, location, and quantity of the fragments produced by calpain I v calpain II. New fragments were detected of approximately 200, 170, 150, and 125 Kd. There was no evidence for generation of the native 140 and 176 Kd fragments. Some loss of the native fragments was seen, which suggests that they were further cleaved. Epitope mapping of the 170- and 150-Kd calpain-cleaved fragments revealed them to be from different parts of the molecule than the regions from which the native 176- and 140-Kd fragments derived. This was further supported by determination of the amino-terminal sequence of the calpain-cleaved 170- and 150-Kd fragments. Digestion of vWF with human leukocyte elastase produced new fragments at 210/205, 190, 170/165, 145/140, and 130/125 Kd. No generation of native fragments was detected. Monoclonal epitope mapping of the 145/140-Kd elastase-cleaved band proved that it derived from the carboxyl-terminal portion of the vWF molecule, whereas the native 140- Kd fragment is derived from the amino-terminal end. Neither calpains nor human leukocyte elastase produced the proteolyzed fragments present in normal and IIA vWD and, therefore, probably do not cause the loss of large multimers that is seen in that disorder.     

Synergistic effects of butyrate on platelet responses to arachidonate, A23187, PGE1, and forskolin

With eukaryotic cells, butyrate is known to induce a series of morphological and biochemical changes that mimic cellular differentiation. With platelets, we have found that butyrate (10 mmol/L) caused an approximately threefold increase in sensitivity to calcium ionophore A23187 and arachidonate. Maximum aggregation was observed at agonist concentrations of 3 mumol/L and 170 mumol/L, respectively, as compared with required concentrations of 10 mumol/L and 400 mumol/L in the absence of butyrate. Similar effects were seen with isobutyric acid, and about one-half the effect was shown with valerate and caproate, but lower homologues showed no synergistic effect. No ultrastructural changes were observed in platelets incubated with butyrate, and the aggregation effects were reversible and returned to normal on removal of butyrate. Membrane fluidity was unchanged by butyrate as measured by changes in the fluorescence depolarization of diphenylhexatriene. Butyrate caused a 60% to 70% increase in the uptake of 3H-arachidonate. Butyrate also potentiated the inhibition of platelet function by prostaglandin E1 and forskolin and uptake of 3H- forskolin was increased approximately 20%. In contrast, platelet response to other agonists (ADP, epinephrine, collagen, thrombin, and platelet-activating factor) was essentially unaffected by butyrate. These results suggest that butyrate may increase the uptake of certain hydophobic agonists and antagonists by platelets. Similar mechanisms for uptake of endogenous effectors may explain the response of eukaryotic cells to butyrate in culture.     

von Willebrand factor and von Willebrand disease [published erratum appears in Blood 1988 Mar;71(3):830]

Progress has occurred in the past several years in the understanding of the structure and function of von Willebrand factor (vWF). This multimeric glycoprotein exhibits a dual role, that of mediating platelet adhesion and aggregation onto thrombogenic surfaces, and that of functioning as carrier in plasma for the factor VIII procoagulant protein. New insights into the nature of the several functional domains of vWF have led to the identification of the regions of the molecule that interact with factor VIII, heparin, the glycoprotein lb of platelets, and collagen. Alterations of vWF are the cause of von Willebrand disease (vWD), a congenital bleeding disorder. In the majority of patients, the plasma levels of vWF are decreased, but there is no demonstrable structural or functional alteration of the protein. In other patients, however, the structure of vWF is abnormal. This review summarizes the current knowledge on vWF and vWD.     

The von willebrand factor domain-mediating botrocetin-induced binding to glycoprotein IB lies between Val449 and Lys728

Botrocetin, a component of Bothrops jararaca venom, induces von Willebrand factor (vWF)-dependent platelet agglutination and has been proposed as an alternative agent to ristocetin for evaluating vWF function. However, important differences between the vWF-platelet interactions induced by these two agents have suggested that different regions of vWF and the platelet may be involved in the interactions induced by the two agonists. We have recently demonstrated that binding of vWF to the platelet glycoprotein (GP) Ib receptor, either induced by ristocetin or as occurs spontaneously with asialo-vWF or vWF from IIb von Willebrand disease, is mediated by a domain residing on a 52/48- kilodalton (kD) tryptic fragment of vWF. This fragment extends from amino acid residue Val (449) to Lys (728). We have now found that this 52/48-kD fragment blocks botrocetin-induced binding of vWF to platelets and completely inhibits botrocetin-induced platelet agglutination. These results provide evidence that the vWF domain-mediating, botrocetin-induced platelet agglutination lies within the region delimited by this fragment and is therefore close to or identical with that which mediates ristocetin-induced binding and spontaneous binding of vWF to platelet GPIb. Anti-GPIb monoclonal antibodies also blocked agglutination, which showed that botrocetin, like ristocetin, induces binding of vWF to the GPIb receptor.